ACTAUNIVERSITATIS

UPSALIENSISUPPSALA

2012

Digital Comprehensive Summaries of Uppsala Dissertationsfrom the Faculty of Medicine 831

177Lu-DOTA-octreotateRadionuclide Therapy ofNeuroendocrine Tumours

Dosimetry-Based Therapy Planning

ULRIKE GARSKE-ROMÁN

ISSN 1651-6206ISBN 978-91-554-8513-9urn:nbn:se:uu:diva-183417

and Outcome

Dissertation presented at Uppsala University to be publicly examined in Ebba Enghoffsalen,Akademiska Sjukhuset Ing. 50, Uppsala, Saturday, December 8, 2012 at 09:15 for thedegree of Doctor of Philosophy (Faculty of Medicine). The examination will be conductedin English.

AbstractGarske-Román, U. 2012. 177Lu-DOTA-octreotate Radionuclide Therapy of NeuroendocrineTumours: Dosimetry-Based Therapy Planning and Outcome. Acta Universitatis Upsaliensis. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine831. 64 pp. Uppsala. ISBN 978-91-554-8513-9.

Peptide receptor radionuclide therapy for the internal radiation of neuroendocrine tumoursexpressing somatostatin receptors has made great advances and offers promising results. 177Lu-DOTA-octreotate is one of the most widely used radiopeptides, but kidneys and bone marrow areorgans at risk. Methods of measuring radiation doses to at-risk organs and tumours (dosimetry)on an individual patient basis have been regarded as impracticable and a maximum of 4 treatmentcycles has widely been accepted as the treatment standard instead.

The first aim of this thesis was to establish a clinically feasible protocol to calculateabsorbed doses to bone marrow and the kidneys during therapy with 177Lu-DOTA-octreotate.A new dosimetry protocol for the bone marrow was described. Dosimetry for solid organs hadpreviously been described based on 3-dimensional imaging by the research group. In the currentthesis it was demonstrated that in most patients only minor changes of the effective half-lifeoccurred in the kidneys. By performing complete dosimetry during the first cycle and comparingit with the uptake in later cycles, it was shown that the absorbed dose can be cal-culated based onthe activity concentration at 24 hours after therapy. The study concluded that 50% of all patientscould receive more than the standard 4 treatment cycles with 7.4 GBq 177Lu-DOTA-octreotatewithout passing the limit of 23 Gray to the kidneys or 2 Gray to the bone marrow, whereas 20%would tolerate fewer than 4 cycles.

The second aim was to describe treatment outcomes of dosimetry-guided therapy with 177Lu-DOTA-octreotate. Patients with metastasized colorectal neuroendocrine tumours and bronchialcarcinoids were shown to have longer survival with this method than previously reported.Morphological tumour response could be correlated to time to progression. Furthermore, in acase of low-differentiated neuroendocrine cancer it was shown that large tumours with highproliferation can also be treated with this method and that tumour-to-risk organ ratios canimprove in later cycles, resulting in a more effective treatment.

Dosimetry-guided, fractionated radionuclide therapy with 177Lu-DOTA-octreotate is avaluable treatment option for patients with advanced neuroendocrine tumours expressingsomatostatin receptors.

Ulrike Garske-Román, Uppsala University, Department of Medical Sciences, Akademiskasjukhuset, SE-751 85 Uppsala, Sweden.

© Ulrike Garske-Román 2012

ISSN 1651-6206ISBN 978-91-554-8513-9urn:nbn:se:uu:diva-183417 (http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-183417)

For Milton

List of Papers

This thesis is based on the following papers, which are referred to in the text by their Roman numerals.

I Garske, U., Sandström, M., Johansson, S., Sundin, A., Gran-

berg, D., Eriksson, B., Lundqvist, H. (2012) Minor changes in effective half-life during fractionated 177Lu-DOTA-octreotate therapy. Acta Oncologica, 51: 86-96

II Sandström, M., Garske-Román, U., Granberg, D., Johansson, S., Widström, C., Eriksson, B., Sundin, A., Lundqvist, H., Lub-berink, M. Individualized dosimetry of kidney and bone mar-row in patients undergoing 177Lu-DOTA-octreotate treatment. Journal of Nuclear Medicine, accepted

III Garske-Román, U., Sandström, M., Johansson, S., Hellman, P., Fröss Baron, K., Lundqvist, H., Sundin, A., Eriksson, B., Gran-berg, D. Favorable outcome of dosimetry-guided therapy with 177Lu-DOTA-octreotate in patients with advanced stages of col-orectal neuroendocrine tumors (NETs) Manuscript submitted

IV Garske-Román, U., Sundin, A., Lindholm, D., Sandström, M., Crona, J., Antonodimitrakis, P., Welin, S., Johansson, S., Eriks-son, B., Granberg, D. Outcome of dosimetry-guided fractionat-ed therapy with 177Lu-DOTA-octreotate in patients with ad-vanced stages of bronchial carcinoids, Manuscript

V Garske U., Sandström, M., Johansson, S., Granberg, D., Lun-dqvist, H., Lubberink, M., Sundin, A., Eriksson, B. (2012) Lessons on Tumour Response: Imaging during Therapy with 177Lu-DOTA-octreotate. A Case Report on a Patient with a Large Volume of Poorly differentiated Neuroendocrine Car-cinoma. Theranostics, 2(5): 459-471

Reprints were made with permission from the respective publishers.

Contents

Introduction ................................................................................................... 11Historical background- the concept of neuroendocrine tumours .............. 11Clinical symptoms .................................................................................... 12

Tumours of the embryonal entoderm ................................................... 13Tumours derived from the neural crest ................................................ 14

The role of nuclear medicine in the management of NETs ...................... 14Nuclear medicine in the diagnosis of NETs ........................................ 15

Treatment .................................................................................................. 16Surgery ................................................................................................. 17Medical treatment ................................................................................ 17Biological treatment ............................................................................. 17Chemotherapy ...................................................................................... 18Radionuclide therapy ........................................................................... 18

Aims of the Thesis ........................................................................................ 21

Materials and Methods .................................................................................. 22Patients ...................................................................................................... 22Therapy and Dosimetry ............................................................................ 23

Paper I .................................................................................................. 23Paper II ................................................................................................. 23Paper III to V ....................................................................................... 25Paper V ................................................................................................. 25

Response evaluation ................................................................................. 26Definition of tumour response, survival and time to progression ............ 26Statistics .................................................................................................... 26

Paper I and II ........................................................................................ 26Paper III and IV ................................................................................... 27

Results ........................................................................................................... 28Paper I ....................................................................................................... 28Paper II ..................................................................................................... 28Paper III .................................................................................................... 29Paper IV .................................................................................................... 30Paper V ..................................................................................................... 32

Tumour response .................................................................................. 32Tumour dosimetry ................................................................................ 35

Discussion ..................................................................................................... 37

Conclusions ................................................................................................... 43Paper I ....................................................................................................... 43Paper II ..................................................................................................... 43Paper III and IV ........................................................................................ 43Paper V ..................................................................................................... 44

Future Perspectives ....................................................................................... 45

Sammanfattning på svenska .......................................................................... 47

Zusammenfassung auf Deutsch ..................................................................... 49

Acknowledgments ......................................................................................... 51

References ..................................................................................................... 55

Abbreviations

AC Atypical carcinoid ACTH Adrenocorticotropic hormone ANOVA Analysis of variance APUD Amine precursor uptake and decarboxylation 11C Carbon-11 CgA Chromogranin A Ci Curie (0.1 Ci=3.7 GBq) CT Computed tomography CR Complete remission g Gramme 68Ga Gallium-68 GBq Giga-Becquerel GEP-NET Gastroenteropancreatic neuroendocrine tumour G 1-3 Grade 1-3 Gy Gray h Hour(s) HED Hydroxyephedrine 5-HIAA 5-hydroxyindolacetic acid 5-HTP 5-hydroxytryptophan 111In Indium-111 keV kilo-electron-Volt Ki-67 Marker for cell proliferation L-DOPA L-hydroxypenylalanine 177Lu Lutetium-177 mCi milli-Curie MEGP Medium energy general purpose (collimator) MIBG Meta-iodobenzylguanidine MIRD Committee on medical internal radiation dose MTO Metomidate m-TOR Mammalian target for rapamycin MR Minor response MRI Magnetic resonance imaging NET Neuroendocrine tumour PD Progressive disease PET Positron emission tomography

p.i. Post injection PR Partial response PRRT Peptide receptor radionuclide therapy RECIST Response evaluation system in solid tumours SD Stable disease SPECT Single photon emission computed tomography ssr2 Somatostatin subtype receptor 2 TACE Transarterial liver chemoembolisation TC Typical carcinoid 99mTc Technetium-99m teff Effective half-life VIP Vasoactive intestinal peptide VOI Volume of interest 90Y Yttrium-90

11

Introduction

Worldwide, an increasing incidence of neuroendocrine tumours (NETs) has been observed[1-6]. Their clinical appearance varies greatly depending on the site of origin, the stage (localized disease or metastases present at diag-nosis), tumour growth (proliferation) and the presence or absence of hormo-nal symptoms[7, 8]. Advances of histopathology have provided a deeper understanding of their origin and explanations for their clinical diversity.

Historical background- the concept of neuroendocrine tumours Neuroendocrine tumours (NETs) are derived from a disseminated system of endocrine cells. The first reports in the literature that may be attributed to the modern concept of NETs were made by Merling when he1838 reported on a tumour in the appendix [9, 10]. Oberndorfer is recognized for coining the term “carcinoids” (carcinoma-like) in 1907 for a new type of tumours, which he originally considered to be benign [11, 12], an opinion he changed in a later publication [13].

Expanding knowledge on structural similarities of neural and endocrine cells evolved. Silver staining techniques for different subsets of cells were developed and became a tool to diagnose tumours derived from what be-came known as the neuroendocrine system. A method originally used for staining nervous cells was modified by Hellman and Hellerström [14] to stain cells in the pancreas (A1 cells), which later on were identified as soma-tostatin producing cells [15, 16]. Masson developed a stain that reacted with endocrine cells in the gastrointestinal wall and bronchi (“Kultschitzky cells”) as well as with carcinoid tumour cells [17]. Depending on whether an oxida-tion step was required or not in order to stain the cells, staining techniques were referred to as “argentaffin” or “argyrophilic”. The Masson stain repre-sents an argentaffin method, whereas the Grimelius stain was an argyrophilic technique, originally described to react with pancreatic A2 cells [18], which later were found to produce pancreatic polypeptide (PP) and glucagon [19]. This method proved to be valuable not only for the identification of tumours of the pancreas, but also of other neuroendocrine tumours derived from the embryonal fore-, mid- and hindgut [20].

12

These staining methods were used for decades for the classification of the tumours of the neuroendocrine system [21]. All silver techniques reacted with so-called dense core granules, later visualised by electron microscopy. These granules stored hormones and were in more recent research found in turn to correlate to Chromogranin A (CgA) expression, a marker widely used for screening and follow-up of NETs [22, 23]. The findings of dense core granules indicated hormonal activity and these storage vesicles of hor-mones in cells derived from the neuroendocrine system became targets for diagnosis and therapy [22, 24].

The work of Friedrich Feyrter (1895- 1973) revolutionized the knowledge on endocrine tumours by introducing a new way of pathophysiological thinking into the contemporary organ-defined pathology. He described dis-seminated cells in the pancreas and gut (”Helle Zellen”), and realized that there were similarities and interactions between the neuronal and endocrine system, forming a network of neuroendocrine cells with local and distant signalling pathways [25-28]. His work made him the father of the concept of “neuroendocrine tumours”. Pearse worked further on Feyrter’s concept of the diffuse neuroendocrine system and described cells characterized by “amine precursor uptake and decarboxylation” mechanisms (APUD cells)[29].

Based on their embryological origin, NETs can be subdivided into tu-mours of the embryonal gut (entoderm) and the neural crest. The latter group comprises a relatively small fraction of tumours with more or less pro-nounced characteristics linking them to the neural system such as pheo-chromocytomas and paragangliomas. Tumours derived from the embryonal entoderm represent the majority of NETs and present with a large diversity in clinical appearance. They all share common properties that link them to the neuroendocrine system, such as the expression of somatostatin receptors and the uptake of amine precursors, characteristics that are used by modern molecular imaging and therapy methods.

Clinical symptoms Depending on their origin, proliferation and hormone production, NETs present with a wide range of clinical appearances. On one end of the spec-trum there are slow-growing tumours that may produce little symptoms over many years, and are sometimes only diagnosed at late stages due to mechan-ical symptoms caused by a large tumour burden. On the other end of the spectrum highly aggressive tumours are found, that lead to severe symptoms and can cause death within a short period of time if not adequately treated.

The other distinctive feature amongst NETs is the production of hor-mones, found in about 10-15% of all patients diagnosed with these tumours

13

[30, 31]. By differentiating the tumours by their embryological origin, dif-ferent groups of hormonal symptoms are found to be associated.

Tumours of the embryonal entoderm Historically, these tumours have been subdivided into endocrine pancreatic tumours and carcinoids, which are further subdivided into carcinoids of the fore-, mid- and hindgut [32].

The largest group of hormonally active tumours occur in the small intes-tine or midgut, with a hormonal syndrome consisting of flushes, diarrhoea, bronchial constriction and at times right heart failure due to thickening of the tricuspid valve [33-35], This syndrome has become known as “classic car-cinoid syndrome” and besides tumours of the small intestine, bronchial and thymic carcinoids as well as tumours of the pancreas are at times associated with these symptoms. In 1953, serotonin was mentioned for the first time as causative agent [36]. In 20-30% of the patients with NETs of the small intes-tine, the classic carcinoid syndrome is present at diagnosis [37], and 85% of the patient will show liver metastases during follow-up [38]. The develop-ment of the carcinoid syndrome is positively correlated to a larger tumour burden in the liver, both situations representing negative prognostic factors for survival [39]. Occasionally, the carcinoid syndrome can become life threatening with symptoms of diarrhoea and severe hypotension. The sero-tonine metabolite 5-hydroxyindolacetic acid (5-HIAA) is a diagnostic mark-er measured in the urine [40].

NETs of the pancreas and duodenum are referred to as “functioning” when associated with clinical symptoms of hormone production, or “non-functioning” in those cases not associated with clinical symptoms. Unlike the carcinoid syndrome of the small intestinal tumours, hormonal active tumours of the pancreas are often small and less often metastasized [7]. Nonetheless, they can give rise to severe symptoms due to a multitude of hormones produced by them, such as insulin, gastrin and vasoactive intesti-nal peptide (VIP), giving rise to hypoglycaemic fits, gastric ulcers or severe diarrhoea and hypovolemia.

The patient’s outcome is dependent on the control of the hormonal symp-toms as well as the degree of tumour malignancy, defined by proliferation and ability to metastasize [8]. Insulinoma are the most common group of hormonal active gastroenteropancreatic NETs, only 5% of them are metasta-sized at diagnosis. In contrast, 40% of gastrinoma are metastasized at diag-nosis, whereas 70-80% of the rare tumours such as glucagonomas and soma-tostatinomas are disseminated at diagnosis [7].

Colorectal NETs are usually not associated with hormonal symptoms and show no elevation of CgA. The majority of them are diagnosed at an early stage and have an excellent prognosis if operable. On the other hand have

14

patients with distant metastases a less favourable prognosis, with only every third surviving 5 years [1].

Bronchopulmonary NETs show a broad range of clinical appearances mostly based on their aggressiveness. They are subdivided into typical (TC) and atypical carcinoid (AC) tumours, large-cell neuroendocrine carcinomas (LCNEC) and the highly malignant small-cell lung carcinomas (SCLC). A minority of less than 5% of bronchopulmonary NETs show hormonal symp-toms, amongst them Cushing’s syndrome related to ACTH production, car-cinoid syndrome and acromegaly [4]. TCs have the best survival prognosis, whereas less than 5% of patients with SCLC survive 5 years.

Tumours derived from the neural crest Tissues and tumours of the neural crest have been shown to express recep-tors for and to produce and to accumulate precursors of catecholamines such as L-DOPA and norepinephrine [41, 42].

Tumours of neural crest origin arise from chromaffin cells, named in analogy with the argentaffin reaction in carcinoids for changing their colour to brown when exposed to chromic salts by complexing catecholamines. These cells share common features with neurons, and hormonal symptoms of the most common of these tumours, the pheochromocytomas are charac-terized by a hyperactivity of the sympathetic nervous system, causing palpi-tations, elevated blood pressure, anxiety and weight loss.

The historical findings of “dense core granules”, the targets of the silver and chromic stains of the pathologists have translated in modern days into findings of hormonal activity and storage vesicles for hormones in cells de-rived from the neuroendocrine system, and have became targets for diagno-sis and therapy[22, 24].

The role of nuclear medicine in the management of NETs Nuclear medicine is a medical speciality providing methods for functional imaging and the treatment of diseases characterized by deranged or impaired cellular function. Especially in the management of neuroendocrine tumours, with a wide range of well-documented and specific targets related to their origin in the endocrine network, nuclear medicine has become a keystone for both diagnosis and therapy. By either labelling hormones themselves or their analogues with detectable radionuclides and/or targeting hormone receptors, neuroendocrine tumours can be imaged, staged and characterized with a specificity that surpasses that for most other tumour groups. By choosing

15

appropriate radionuclides for treatment, the same mechanisms can also be used for radionuclide therapy.

Nuclear medicine in the diagnosis of NETs For imaging, tracing agents can be labelled with either gamma emitting ra-dionuclides for conventional gamma camera examinations, or positron emit-ting radionuclides for PET (positron emission tomography). Imaging on gamma cameras can either be performed in two dimensions (static images or whole body scans), or in three dimensions with single photon emission computed tomography (SPECT). PET radionuclides often have half-lives within minutes or hours. In tissue the emitted positron and an electron anni-hilates, sending out two opposite directed annihilation photons with an ener-gy of 511 keV each. In a PET camera these photons can be detected simulta-neously by a large number of detectors placed in several rings, providing images of high resolution. Whereas the high image resolution is a great advantage of PET tracers, their short half-life of the tracers and limited availability is a restricting factor. Conventional gamma emitting radionuclides can be chosen for their imaging and labelling properties, with different physical half-lives adjusted to the processes to be studied. Also, gamma decay can be found in a range of radi-onuclides with good properties for therapy, making them ideal for imaging during therapy for dosimetry and response monitoring. In modern applica-tions, both SPECT and PET cameras are usually combined with a computer tomograph (CT), for both attenuation correction and improved anatomic information.

Tracers targeting hormone synthesis and amine precursor uptake mechanisms Meta-iodobenzylguanidine (MIBG) is a norepinephrine analogue that uses the amine precursor uptake mechanism and may be incorporated in vesicles or neurosecretory granules of cells derived from the neural crest. It was de-veloped for visualizing the adrenal medulla [41]. Later on, it became widely used for the staging of tumours derived from the neural crest, especially neuroblastoma in children [43, 44] and pheochromocytomas and paragangli-omas in adults [44, 45]. Even medullary thyroid tumours, carcinoids of dif-ferent origin and pancreatic NETs were shown to take up MIBG, but was found to be less sensitive for the detection of these tumours than somatosta-tin analogues [46, 47]. For PET imaging, hydroxyephedrine (HED) labelled with 11C was introduced [48-52], rendering excellent information on the stage of patients with neural crest tumours. The complexity of 11C chemistry

16

and the short half-life of the isotope of about 20 minutes restrict the applica-tion of 11C –labelled tracers to specialized centres.

Another enzyme involved in the synthesis of corticoid hormones in the cortex of the adrenal gland, metomidate, has been shown to be a sensitive and specific PET tracer for adrenocortical tumours when linked to Carbon-11 (11C-MTO) [53-55].

Knowledge of the decarboxylation mechanisms that convert amine pre-cursors into active peptide hormones became important to develop PETtrac-ers for the detection of neuroendocrine tumours. PET with 11C- and 18F-labelled L-hydroxypenylalanine (L-DOPA) and 11C- labelled hydroxytrypto-phan (5-HTP) increased the sensitivity and specificity for detection of NETs and became an important contribution to the correct staging of these patients [56-60].

Tracers directed towards somatostatin receptors Somatostatin receptors are widely expressed in neuroendocrine tumours. In 1989 Krenning et al reported on the scintigraphic visualisation of several neuroendocrine tumours by using a synthetical somatostatin analogue, 123I-labelled Tyr-3-octreotide [61]. This was the start of a development that should produce several somatostatin analogues binding to the somatostatin receptors. 111In-labelled DTPA-octreotide, with high affinity especially to somatostatin receptor type 2 became the gold standard for the diagnostic of neuroendo-crine tumours [62-66] and became commercially available. It serves for stag-ing the tumour extent and is a predictor of responsiveness to treatment with somatostatin analogues, unlabelled or, in recent years for the therapy with radiolabeled somatostatin analogues. 111In has a relatively long half-life of 2.81 days that suited the purpose of imaging after 24 hrs, where best tumour identification was found for this tracer. In recent years, new tracers for both gamma camera imaging and PET imaging have been developed. 99mTc la-belled EDDA/ HYNIC-TOC is available for gamma camera imaging using a one-day protocol [67, 68].

Several reports on 68Ga-labelled somatostatin analogues have been pub-lished during the last few years. Because of the better sensitivity and image quality combined with shorter imaging protocols PET with 68Ga-labelled somatostatin analogues will most probably replace111In-DTPA-octreotide scintigraphy in the near future [69-72].

Treatment Treatment of NETs is, as for any tumour, largely dependent on the stage of the disease. Different strategies are necessary in the case of localized com-

17

pared to disseminated disease. Management of hormonal symptoms is often a challenging task and closely interconnected with the response to given therapy.

Surgery For localized NETs, surgery is the treatment of choice. If the tumour is de-tected at an early stage, surgery is for many patients curative. When metasta-ses have occurred, surgery has its place as a component in a multidiscipli-nary approach with the goal to ameliorate symptoms, prevent complications and prolong life [73, 74]. Early surgery in the course of disease may also decrease the risk for development of metastases and consecutively, improve survival [73, 75, 76]. Stenting procedures can alleviate symptoms of vessel obstruction in the mesenteric root [77]. After resection of pancreatic NETs, progression occurs predominantly in distant sites, resulting in the need for systemic treatment [78, 79].

Medical treatment Biological treatment

Somatostatin analogues Many neuroendocrine tumours express receptors for somatostatin, a regula-tory peptide hormone involved in growth control and neurotransmission. In its endogenous form, it exists in two active forms consisting of 14 and 28 amino acids, respectively. Their physiological half-life is short, in the range of minutes. In humans, 5 different receptor subtypes for somatostatin are known, of which receptor type 2 (ssr2) is most often overexpressed in neu-roendocrine tumours [80, 81]. Therapy with somatostatin analogues have been proven to result in increased symptom control by decreasing the hor-mone production in neuroendocrine tumours, especially in patients with classic carcinoid syndrome, but the effect on survival has still to be proven in randomised studies. Decrease of tumour burden is rarely noticed during treatment with somatostatin analogues [37, 82, 83].

Alpha interferon Alpha Interferon in combination with somatostatin analogues is the standard regime in modern treatment of midgut carcinoids, and can also be used in patients with GEP-NETs of the pancreas and duodenum. It reduces hormone levels in 50% of the patients and reduces tumour size in 15% [79]. It has been proven to ameliorate the carcinoid syndrome, reduces tumour growth and prolongs survival.

18

Chemotherapy Treatment with cytostatic agents has no place in the management of car-cinoids of the small intestine.

For patients with well-differentiated metastasised endocrine pancreatic tumours, chemotherapy with a combination of streptozotocin with 5-fluorouracil or doxorubicin is first-line therapy [84]. In this group of pa-tients, the median survival is reported to be in the range of 2 years, with a response rate of 35 to 60% [85, 86]. Also temozolomide has shown some efficacy in patients with well or intermediate differentiated endocrine pan-creatic and duodenal tumours [87].

For patients with advanced disseminated tumours of the hindgut (colorec-tal NETs) as well as the stomach, there is no established first-line treatment [88, 89].

Few chemotherapy regimens have proven effective in treating metastatic bronchial carcinoids, with overall discouraging results [90]. Cisplatinum + etoposide as well as paclitaxel have demonstrated some efficacy [91, 92], and studies of a limited number of patients indicated that temozolomide may be effective as monotherapy [87, 93] (Table 1).

For patients with low differentiated neuroendocrine tumours, disregarding origin, platinum-based chemotherapy in combination with etoposide is first-line treatment [88, 94], but also temozolomide has been applied [95] . Espe-cially cisplatinum is a cytostatic drug with severe potential side effects such as nausea as well as oto-and nephrotoxicity, with consecutive impairment of the quality of life [96]. Newer drugs such as tyrosinkinase inhibitors, mTOR-antagonists and neoangiogenesis inhibitors are still under clinical evaluation [97].

Radionuclide therapy Besides MIBG, the radionuclide therapy of neuroendocrine tumours has been dominated by the targeted therapies directed towards somatostatin re-ceptors mainly of subtype 2.

After successfully visualizing somatostatin receptors with 111In-DTPA-octreotide, the next step was to its application for therapy [98]. 111In decays by electron capture and is mainly a gamma-emitter suitable for diagnostics, but some low energy conversion and Auger electrons in its decay encour-aged clinical trials to use it for therapy as well [98-100]. Therapy with 111In-DTPA-octreotide was found clinically promising with symptomatic relief, but only rarely resulting in a morphologic tumour response [101]. The beta-emitting radionuclides 90Y and 177Lu were found more interesting, due to the more favourable ratio between gamma radiation and charged particles hav-ing a longer range in tissue that made them more suitable for macroscopic

19

tumours [102, 103]. Changes in the peptide structure and chelator improved the binding capacities of the radiopharmaceutical and the stability of the complex. Several studies with 90Y-DOTA-octreotide (90Y-DOTATOC) were performed in order to find optimal activities [104-109] with objective re-sponses found in between 9-34% of the patients [109, 110]. Large variations in the patient populations and the therapy protocol make comparisons be-tween studies difficult.

One side effect of the treatment turned out to be kidney failure, especially when re-absorption of the excreted radiopharmaceutical was not blocked by concomitant amino acid infusions [104, 111-114]. A large series of 1109 patients treated in Basel between 1997 and February 2010 was reported on recently, with a morphological response rate of 34.1% (any degree). The treatment was given as single infusions of 3.7 GBq 90Y-DOTATOC/m2 bodysurface, median number of cycles were 2. For kidney protection, a con-comitant infusion of a mixture of arginine and lysine was given during 4 hours, commencing 30 min before the radionuclide therapy. In this group, 103 (9.2%) patients developed permanent kidney toxicity (grade 4 and 5). Reversible haematological toxicity grade 3 and 4 was seen in 12.8% of the patients. Morphological response was seen to correlate with longer survival, and the outcome of patients with high tumour uptake was better.

Therapy with 177Lu-DOTA-octeotate has been developed in parallel. DTPA-octreotate was shown in a preclinical evaluation found to have better binding capacities as compared to DTPA-octreotide [115]. Two years later, DOTA-octreotate was shown in vitro to have a higher affinity for somatosta-tin receptors type 2 as compared to DOTA-octreotide [116], the predominant receptor type in NETs. In comparison to 90Y, 177Lu has a longer physical half-life and a shorter beta particle range in tissue. With a half-life of 6.68 days 177Lu has a lower dose-rate than 90Y with 64 hours. The longer range in tissue of 90Y implies a more homogeneous absorbed dose distribution in tumours, but also in the kidney as compared to 177Lu and 111In as shown by Konijnenberg et al [117]. The authors concluded that existing models for predicting kidney damage based on average dose to the kidney or cortex from external beam therapy experi-ence are most probably not applicable for those radionuclides. Results from therapy with 177Lu-DOTA-octreotate have in fact shown that the kidney toxicity in patients treated with this radiopeptide is much lower than with 90Y-DOTATOC [118, 119]. Results from both 90Y-DOTATOC and 177Lu-DOTA-octreotate have shown results that compare favourably to results from other systemic treatment for different types of NETs [99, 118-121]

Dosimetry is a tool to measure absorbed doses in tissue and to predict and control effect and side effects. The absorbed dose is defined by the amount of energy deposited by ionizing radiation by unit mass. It is measured in Gray (Gy; Joule/kg). The use of dosimetry is well established for external

20

beam radiation, and dosimetry during radionuclide therapy often relates to the experiences from this treatment form [122]. The experience from exter-nal beam radiation is not easily transferred to the special conditions of radi-onuclide therapy. Doses in radionuclide therapy will vary due to changes in uptake, and it is a low-dose-rate radiation to which the body is exposed un-der a longer time. If dose calculations have been applied, they were often based on 2D imaging[123-125]. This method has major drawbacks, since overlap of tumour uptake can prevent the exact measurement of uptake in risk organs. Furthermore, it is difficult to estimate organ sizes with any pre-cision, and organ sizes can vary substantially, as previously shown [126]. A new way of calculating absorbed doses based on SPECT-CT was developed at the University Hospital of Uppsala. This method uses small volumes of interest (VOI) in order to measure activity concentration at 24 hours, 4 and 7 days in solid organs following therapy with 177Lu-DOTA-octreotate in order to calculate absorbed doses to kidneys, spleen and tumour-free liver paren-chyma[126]. After a study with increasing amounts of activity per cycle up to an accumulated activity of 600-800 mCi [118] most therapy reports for 177Lu-DOTA-octreotate are based on a protocol of up to 4 cycles with 200 mCi corresponding to 7.4 GBq up to a maximum of 800 mCi (29.6 GBq) [119, 123]. Calculations made by the group in Rotterdam, the leader in the development of therapy with 177Lu-DOTA-octreotae, indicated that a sub-stantial amount of their patients might not reach an accumulated dose of 23 Gy to the kidneys by an accumulated activity of 800 mCi [110]. This upper limit of activity was accepted in the first place, since bone marrow dosimetry in a group of six patients with limited disease showed an absorbed dose of 260mGy/100 mCi, reaching in the accepted accumulated dose of 2 Gy to the bone marrow with 800 mCi [127]. However, later results by the same group contested this result, showing that bone marrow doses in different patients varied more than previously assumed, and doses to the bone marrow found in this study were lower than previous data indicated[128]. This opened for the thought that a subset of patients may be undertreated with a fixed treat-ment schedule of 4 cycles with 200mCi (7.4 GBq) of 177Lu-DOTA-octreotate [110]. Later results indicated also that patients with progressive disease after successful initial therapy with 177Lu-DOTA-octreotate could safely be retreated with further cycles [129].

With the aim to further increase the efficacy of therapy with radiolabelled somatostatin analogues, combinations of different radionuclides have been suggested [130, 131], as well as the combination with radiosensitizers [132-134].

21

Aims of the Thesis

Peptide receptor radionuclide therapy has increased in importance for the management of patients with generalized neuroendocrine tumours (NETs). The first part of the thesis aimed to develop an individual dosimetry protocol for patients undergoing therapy with 177Lu-DOTA-octreotate that could work in the clinic, as a tool for measuring absorbed doses to risk organs and tu-mours for an optimized treatment (Papers I and II). The aim of the second part was to describe the outcome of fractionated, dosimetry-guided therapy in patients with advanced stages of neuroendocrine tumours (Papers III-V). Specific aims were

• To investigate the effective half-life of 177Lu in solid organs during

therapy and the possibility to customize measurements in subse-quent treatment cycles (Paper I)

• To develop a protocol for bone marrow dosimetry and to estimate the possible number of treatment cycles for individual patients be-fore reaching an accumulated absorbed dose of 23 Gray (Gy) to the kidneys or 2 Gy to the bone marrow (Paper II)

• To investigate the outcome of dosimetry-guided therapy with 177Lu-DOTA-octreotate in patients with metastasized colorectal NETs (Paper III) and bronchial carcinoids (Paper IV) regarding morphological tumour response, time-to-progression and survival

• To describe the changes in uptake and absorbed doses in tumours, kidneys and bone marrow in a patient with a poorly differentiated neuroendocrine carcinoma (Paper V)

22

Materials and Methods

Patients All patients described in this thesis suffered from metastasized NETs with high somatostatin receptor expression (grade 3 or 4).

Since September 2010, all patients have been included into a prospective study (EudraCT nr 2009-012260-14), approved by the Regional Ethical Re-view Board in Uppsala, after signing a written informed consent. Before this time, patients were admitted on a single patient basis for compassionate use with individual permission of the Swedish Medical Products Agency.

For paper I, 30 patients with different tumours diagnoses were analysed. At least two complete dosimetry calculations during their therapy with 177Lu-DOTA-octreotate were performed. In paper II, 200 consecutive patients with NETs of different origin undergo-ing therapy with 177Lu-DOTA-octreotate were included. Paper III reports the outcome of 16 patients with advanced colorectal NETs in stage IV, 8 men and 8 women. Ki-67 was available for 15 patients, 13 patients had G2 tumours, one patient each a G1 and G3 tumour. In 12 pa-tients, the primary tumour had been operated; one patient had received ex-ternal beam radiation for the primary. Six patients had been treated with chemotherapy, one had had a liver transplant, one patient each had been treated with transarterial liver chemoembolization (TACE) and bland liver embolization. Four patients had been treated with somatostatin analogs, two of them in combination with alpha-interferon. Nine patients were in progres-sion at the start of therapy, four received 177Lu-DOTA-octreotate as a first line therapy. Liver metastases were seen in 14 patients (87.5%), bone and bone marrow metastases in 10 (62.5%).

Paper IV reports on thirteen patients with metastatic bronchial carcinoids treated with 177Lu-DOTA-octreotate between 2006 and 2011. Five were classified as atypical and four as typical carcinoids. Histological classifica-tion was unavailable for four tumours. All patients had advanced metastatic disease (stage IV). Eight patients had previously received chemotherapy, six were receiving treatment with somatostatin analogues, and one patient had had a liver transplant. Paper V is a case report on a 42-year-old woman with a poorly differentiated neurendocrine carcinoma of unknown origin previously unresponsive to two different chemotherapy protocols. She had a large tumour burden in the liver

23

as well as enlarged abdominal, thoracic and pelvic lymph nodes. Small bone metastases were suspected in the sacrum and the thoracic spine. Liver biop-sies at two different time points from several liver metastases revealed a Ki-67 rate between 10 and 50%. Somatostatin receptor scintigraphy showed very high uptake (grade 4) in all known tumour lesions. She received 7 cy-cles of 7.4 GBq 177Lu-DOTA-octreote guided by dosimetry, aiming at an interval of 6 to 8 weeks. Two (first 5 cycles) to four litres (cycle 6 and 7) of a mixed amino acid solution were co-infused at an infusion speed of 250mL/min commencing 30 min before the radionuclide infusion.

Therapy and Dosimetry DOTA-Tyr-3-octreotate was a generous gift from Prof. Eric Krenning (Erasmus Medical Centre, Rotterdam). 177LuCl3 was purchased from IDB (Petten, The Netherlands). The labelling procedure was performed in-house prior to the infusion. For kidney protection, a mixed amino acid solution (Vamin 14gN/L electrolyte-free, Kabi Fresenius ®) was administered. Until Autumn 2008, all patient received 1 liter, which after results from the dosi-metric studies was increased to 2 liters.

Paper I Calculation of absorbed doses to kidneys, spleen and liver at their first and 4th cycle performed on 3-D data was based on SPECT/CT images acquired at 24 hours, 4 and 7 days after infusion of the radiopeptide. A previously described measurement of activity concentration in small volumes of interest in kidneys, spleen and liver was applied [126] and the effective half-life (teff) as well as the absorbed doses in the organs were calculated. Ratios of the results obtained at the fourth and the first cycle results were formed.

Paper II All patients underwent whole-body gamma scintigraphy (anterior and poste-rior planar acquisitions) and SPECT/CT of the abdomen at 24, 96 and 168 hours after administration of the first therapeutic dose of 7.4 GBq 177Lu-DOTA- octreotate. For the first 69 patients, imaging was performed on a Hawkeye Millennium VG (International General Electric, General Electric Medical Systems, Haifa, Israel) dual-headed gamma camera equipped with 5/8” NaI(Tl)-crystals with VPC-5 (MEGP) collimators. For those patients, a 20% energy window around the two dominant gamma ray energies of 177Lu, 113.0 and 208.4 keV, was used. For the other 131 patients, imaging was performed on an Infinia (International General Electric, General Electric

24

Medical Systems, Haifa, Israel) dual-headed gamma camera equipped with 3/8” NaI(Tl)-crystals with VPC-5 (MEGP) collimators. A 20% energy win-dow was placed around the dominant 208.4 keV gamma ray energy of 177Lu to make the measurements. Imaging with whole body scintigraphy and SPECT/CT was performed as described earlier [126]with the exception that SPECT/CT images were collected with 120 angles with 30 s per frame for the Infinia. Calibration of whole body and SPECT images was based on a 100 ml sphere containing a known amount of activity placed inside a thorax phantom, which was scanned repeatedly. Phantom measurements confirmed that there were no dead time issues in the patient measurements.

Blood samples were drawn from the venous catheter in which the amino acid solution was infused, after rinsing with 10ml of 0.9% saline. Blood samples (∼3 g) were drawn at 0.5, 1.0, 2.5, 4, 8 and 24 h after start of 177Lu-DOTA-Tyr-3-octreotate administration. In the first 50 patients, additional samples were collected at 96 and 168 h post injection (p.i). Time In 50 pa-tients, additional blood samples were obtained at 96 and 168 h. Moreover, urine was collected from 30 patients during the first 24 h. The absorbed ra-diation dose to the bone marrow was calculated based on blood and urinary activity curves over time combined with organ-based analysis of the whole body images. The absorbed dose to the kidney was calculated from the pharmacokinetic data obtained from SPECT/CT.

Blood kinetics was analyzed using a bi-exponential model. In 5% of the patients, this model could not explain the blood kinetics, which was the main reason why trapezoidal integration was used to estimate the time-integrated activity concentration for the first 24 hours. For the second phase (after 24h) a single exponential function was assumed with a half-life of 72h that was integrated between 24 h and infinity. The value 72h was taken as an upper value derived from patients in whom late blood samples were taken and that all showed a half-life in blood for the second phase shorter than 72 hours. The late blood phase in all patients was therefore assumed to follow a single exponential curve and was integrated between 24 h and infinity using an effective half-life of 72 h. Assuming that the activity concentration in bone marrow was the same as in blood [128] the time integrated activity concen-tration obtained for blood was also applied for the calculation of the bone marrow self-dose.

Urine was collected from 30 male patients from the start of infusion and during approximately 24 hours. The first eight urinations were collected in separate vessels while further urinations were pooled in a ninth container. Samples of about 0.1g each were taken. From these samples, the total amount of excreted activity from the body during the first 24 hours was cal-culated and added to the measured total body activity as calculated from the whole-body scintigraphy after 24 hours. The value obtained was compared

25

to the administered activity to ensure that the two measurements yielded an activity recovery close to 100%.

The kinetic of the urine excretion was then used to calculate the whole body excretion kinetics and the related activity kinetics in large organs dur-ing the first 24 hours. Single measurements were made at 24, 96 and 168 hours. The cumulative activities in large organs were then used as input into a MIRD phantom model to calculate the cross-fire dose to the bone marrow.

The results of the bone marrow dosimetry were combined with those from 3D based kidney dosimetry in order to estimate the maximum tolerated number of cycles with 177Lu-DOTA-octreotate before reaching an accumu-lated dose of 2 Gy to the bone marrow or 23 Gy to the kidneys.

Paper III to V The patients were treated with between two to eight cycles of 7.4 GBq 177Lu-DOTA-octreotate guided by dosimetry as described in [126], Paper I and II, aiming at an accumulated dose of 23 Gray (Gy) to the kidneys or 2 Gy to the bone marrow.

Within kidneys, liver spleen and representative tumours, small volumes of interests (VOIs) of 4 ml were drawn in areas with homogeneous activity distribution on SPECT-CT images performed at 24 hours, 4 and 7 days after the first cycle. During following cycles, the uptake intensity in tumours and kidneys was calculated based on 24 hrs post therapy imaging with SPECT-CT and whole body scan, assuming the same effective half-life as calculated from the previous complete dosimetry. When larger changes in the uptake pattern and tumour burden occurred or anticipated by the clinical aspect, complete dosimetry was repeated.

Bone marrow dosimetry was based on a) calculation of the self-dose de-rived from the blood and b) calculation of the dose contribution from the rest of the body including tumours, based on whole body scans according to Paper II.

Paper V Full dosimetry for solid organs and tumours was performed during cycles 1, 3 and 6, based on SPECT with low-dose CT at 24 hrs, 4 and 7 days after therapy. For bone marrow dosimetry, whole body scans acquired at the same time points were combined with blood activity curves over time calculated from six venous blood samples taken during the first 24 hours after the infu-sion, starting directly after the rinsing was finished. For dosimetry during cycle 1, the reported tumour-VOIs were drawn in areas representing the highest uptake within the respective metastasis. For the subsequent calcula-tions the same areas within the tumours were identified.

26

Response evaluation Paper III-V: Morphologic response evaluation was performed according to RECIST 1.1 criteria [135] by contrast-enhanced computed tomography (CT) after every second cycle, three months after finished therapy and then every 6th month.

Complete response (CR) is defined as total disappearance of a tumour le-sion on (CT), partial response (PR) is equivalent to a decrease of the sum of evaluable tumour diameters by 30% or more, progressive disease (PD) to an increase of 20% or more and/or the apperance of new tumour lesions. Stable disease (SD) is stated if neither criteria for PR nor PD are fulfilled.

When bone metastases (not evaluable according to RECIST criteria) dominated the tumour burden, magnetic resonance imaging (MRI) in com-bination with positron emission tomography (PET-CT) was applied using 11C-5-hydroxytryptophan (11C-5-HTP)[60, 136, 137] in order to detect new lesions.

Definition of tumour response, survival and time to progression For statistical analysis, the best morphological response according to RE-CIST 1.1 was considered. Progression was defined as morphological tumour growth after the start of therapy with 177Lu-DOTA-octreotate, development of new metastases or a decrease of peripheral blood counts that were as-cribed to bone marrow metastases. Survival was calculated from start of therapy and month of diagnosis.

For the nine Swedish patients, survival data were obtained from the civil registration register. For the remaining seven patients, survival data were calculated from the date of last contact. Time to progression was defined from the start of therapy to morphologically confirmed progression based on CT or functional imaging when CT or MRI was inconclusive.

Statistics Paper I and II Data were analyzed with an Anderson-Darling test in order to check for normal distribution. Since only half of the data sets passed the test, all data were analyzed as being non-normally distributed. Blood and organ activity concentration data were fitted to exponential functions using the least square

27

method and the coefficient of multiple determination (R2) was calculated. A non-parametric Wilcoxon paired test was applied to a) test differences be-tween the measured total body activity at 24 h p.i and injected activity minus all activity collected in urine during 24 h, b) the absorbed dose to the bone marrow at a later cycle compared to that of the first cycle and c) the data for the dose limiting organ. The median, 1st quartile and the 3rd quartile was calculated for the two phases of the effective half-life of the fit to the bi-exponential function of the blood concentration and the remainder of the body. For the R2-calculations, the total body recovery and the ratio between the absorbed dose to the bone marrow at a late therapy cycle divided by that of the first cycle the following, data are in the following presented as median (1st quartile - 3rd quartile). Statistical significance was assumed at p < 0.05.

Paper III and IV Statistical analysis using the JMP 10 software package (SAS Institute Inc., SAS Campus Drive, Cary, North Carolina 27513, USA) included distribu-tion analysis, survival analysis (Kaplan-Meier) and bivariate linear regres-sion analysis. Analysis of variance (ANOVA) was performed for the regres-sion analysis. Statistical significance was assumed at a p-value of <0.05.

28

Results

Paper I The effective half-life (teff) in kidneys and liver decreased in most of the patients during therapy, resulting in mean ratios slightly lower than one. The variation in the data was small for the kidney and the spleen. Some of them, however, showed a marked decrease in both kidneys. All patients with a substantial decrease of tumour burden during therapy were found in the lat-ter group. By contrast, two patients showed a striking increase of teff . The first patient who had more than 20% increase received 2 L of amino acid infusion during the first cycle of therapy, but only 1 L during the latter cycle.

Paper II For a single cycle of 7.4 GBq, the absorbed dose to the bone marrow and the kidney ranged 0.05 to 0.4 Gy and 2 to 10 Gy, respectively. In 197 of 200 patients, the kidneys accumulated an absorbed dose of 23 Gy before the bone marrow reached 2 Gy. Between 2 and 10 cycles of 177Lu-DOTA-octreotate could be administered until the upper dose limit for the individual patient was reached (Figure 1).

Figure 1 Maximum number of cycles with 7.4 GBq of 177Lu-DOTA-octreotate per patient before reaching 2 Gy to the bone marrow or 23 Gy to the kidney

29

Paper III Twelve of the 16 patients with the advanced colorectal NETs (75%) reached an accumulated absorbed dose to the kidneys of 23 Gy, ten during the initial therapy and two after progression. None reached an accumulated dose to the bone marrow of 2 Gy. Median follow-up time was 42 months from start of therapy (range 13-80). No major toxicity was observed. No complete remis-sions were observed. Thirteen patients (81.3%) showed a morphological response with a decrease of the tumour burden of between 14 and 94%. Of these, nine patients (9/16; 56%) obtained partial remission (PR). One patient progressed (PD). The median overall survival was 58 months (Figure 2).

Figure 2 Survival of 16 patients with advanced colorectal NETs from start of dosim-etry-guided, fractionated therapy with 177Lu-DOTA-octreotate (Kaplan-Meier).

Six patients (37.5%) died of progressive disease. In six patients who did not receive 23 Gy to the kidneys during the initial treatment, the median time to progression was 24.5 months and for those who reached 23 Gy at the initial therapy, it was 37 months (Figure 3).

Figure 3 Time to progression of patients with advanced colorectal NETs after start of fractionated, dosimetry-guided therapy with 177Lu-DOTA-octreotate subdivided into patients that received an accumulated absorbed dose of 23 Gy to the kidneys at initial therapy (blue line) and those that did not (red line)

0%

20%

40%

60%

80%

100%

Surv

ivin

g Pa

tient

s

10 20 30 40 50 60 70 80Survival From Start of Therapy (Months)

0%

20%

40%

60%

80%

100%

Prog

ress

ion-

Free

Pat

ient

s

10 20 30 40 50 60 70Time to Progression (Months)

median TTP 37

median TTP 24.5 months

Median Surviv-al 58 months (combined data)

30

A correlation with R2 of 0.53 was demonstrated between morphological response and time to progression (Figure 4).

Figure 4 Correlation between morphological response assessed according to RE-CIST 1.1 criteria and time to progression in 16 patients with advanced colorectal NETs after fractionated, dosimetry-guided therapy with 177Lu-DOTA-octreotate

Paper IV Median follow-up was 35 months from treatment start (range 11-54) and 118 months from initial diagnosis (range 24-278). Partial response according to RECIST 1.1 was seen in 5/13 patients (PR 38.5%), stable disease in 6/13 (SD 46.2%) and 2/13 patients progressed (PD 15.4%). Ten patients experi-enced some degree of morphological tumour decrease (76.9%). From thera-py start, the median overall survival was 44 months (Figure 5) and the medi-an progression-free survival was 37 months.

Figure 5 Survival of 13 patients with advanced bronchial NETs after start of fractionated, dosimetry-guided therapy with 177Lu-DOTA-octreotate; Blue dots: progression-free pa-tients at time of analysis

-100

10203040506070

Tim

e to

Prog

ress

ion

(Mon

ths)

-100 -80 -60 -40 -20 0 20 40Best Response (%

according to RECIST 1.1)

0%

20%

40%

60%

80%

100%

Patie

nts

Aliv

e

10 15 20 25 30 35 40 45 50 55Survival after Start of 177Lu-DOTA-octreotate

(Months)

median survival 44 months

31

At the time of analysis, seven patients are alive, six of them progression-free with a median follow-up of 41 months (range 16 to 54). From initial diagno-sis, overall survival was 138 months. A correlation with R2= 0.63 was seen between degree of morphological response and progression-free survival.

Figure 6 Correlation between best morphological response according to RECIST 1.1 criteria and progression-free survival in 13 patients with advanced bronchial carcinoids after fractionated, dosimetry-guided therapy with 177Lu-DOTA-octreotate. R2= 0.63. Blue dots: progression-free at time of analysis, red dots: pa-tients have progressed

Immediate bone marrow toxicity was mild, but one patient with previous temozolomide therapy developed acute leukemia 16 months after the start of therapy. No kidney toxicity occurred. An overview of therapy protocols for advanced bronchial carcinoids with reported morphological outcome, mean or median survival data, time to progression and progression-free survival is shown in table 1.

10152025303540455055

Prog

ress

ion-

Free

Sur

viva

l (M

onth

s)

-70 -60 -50 -40 -30 -20 -10 0 10 20Best Response RECIST 1.1 (%)

32

Table 1 Overview of treatment results in patients with advanced bronchial carcinoids

α

TC: typical carcinoid, AC: Atypical Carcinoid, NN: unknown; SD: stable disease, PR: partial response, PD: progressive disease; EBR: external beam radiation; TTP: time to progression, PFS: progression-free survival; CI: confidence interval

Paper V Tumour response Combined chemotherapy managed to decrease only slightly the diameter of a pelvic tumour, while all other metastases continued to grow in size.

After the initiation of 177Lu-DOTA-octreotate, all metastases decreased and continued to do so at subsequent times of evaluation (Figure 7 and 8). Three months after cycle 7, all liver metastases showed radiological signs of necrosis. At this time, the sum of the tumour diameters had decreased by 44% according to RECIST 1.1 since start of therapy, corresponding to a partial remission (PR). Also according to the scintigraphy acquired during each cycle, the total tumour burden continued to decrease throughout the whole therapy.

33

Table 1 continued

Figure 7 Whole body scan (cropped) at 24 hours after each cycle with 7.4 GBq 177Lu-DOTA-octreotate in patient with advanced, poorly differentiated neuroendo-crine carcinoma.. Upper row: anterior view, lower row: posterior view. Note the decrease of tumour uptake and the change of uptake pattern

34

Figure 8 Diameters of the 5 largest metastases in the liver of a patient with poorly differentiated NET of unknown origin. Increase of tumour burden under therapy with cisplatinum and etoposide followed by temozolomide in combination with capecitabine . After start of therapy with 7 cycles of fractionated, dosimetry-guided 177Lu-DOTA-octreotate, subsequent tumour decrease occurred.

After seven cycles of 177Lu-DOTA-octreotate with 7.4 GBq each, dosimetry indicated an accumulated absorbed dose to the right kidney of 25.4 Gy and 24.4 Gy to the left kidney. The absorbed doses to the kidneys remained es-sentially on the same level during the first 4 cycles, but increased slightly towards the end of the treatment (Figure 9).

Figure 9 Absorbed doses to kidneys, liver, spleen, bone marrow and representa-tive tumours in a patient with poorly differentiated neuroendocrine carcinoma undergoing fractionated, dosimetry-guided therapy with 177Lu-DOTA-octreotate

35

The dose to the spleen decreased slightly over time. The absorbed dose to the bone marrow decreased throughout the treatment, both the self-dose calculated from the blood activity (89, 75, and 60 mGy at cycle 1, 3 and 6), as well as the photon contribution from solid organs, tumours and the re-mainder of the body (121, 106 and 78 mGy, respectively) (Figure 9).

Tumour dosimetry Applying the same method for dosimetry as described for solid organs also to the tumours, all measured tumours increased their activity concentration and, as a consequence, the absorbed dose throughout the course of therapy. The activity distribution grew more homogeneous during the treatment, while the tumour appeared to shrink concentrically according to the fused SPECT-CT images (Figures 10 and 11). The more homogeneous activity distribution in the remainder of the large liver metastases is obvious in Fig-ure 10.

Figure 10 Sagittal view of SPEC-CT over the abdomen at the level of the right kid-ney, 24 hours after infusion of 7.4 GBq of 177Lu-DOTA-octreotate. Left: Cycle 1, May 2010. Right: Cycle 7, August 2011. Left upper corner in each image: attenua-tion correction CT, right upper corner attenuation corrected SPECT, left lower corner fused SPECT-CT, right lower corner maximum intensity projection (MIP). Note the position of the right kidney (arrow) and tracer distribution within the tu-mours.

36

Figure 11 SPECT

37

Discussion

Malignant tumours, though not curable, can be controlled for an extended period of time [40]. In the special case of neuroendocrine tumours both symptoms caused by tumour growth as well as hormone production need to be treated. Thus, it is of great importance to choose the treatment with best efficacy and lowest degree of side effects.

In this thesis a clinically feasible approach on dosimetry is described, to optimise internal radiation with 177Lu-DOTA-octreotate. This method also presents an opportunity to monitor and understand in greater detail the dy-namic changes of uptake during therapy and the radiobiological implications of it.

Paper I reports on the fact that the effective half-life especially in the kid-neys changes only to a minor extent, opening for the possibility to reduce imaging during subsequent cycles, without compromising the prerequisites to calculate absorbed doses in solid organs.

Paper II focuses on the main organs at risk during radionuclide therapy, bone marrow and kidneys. A method of calculating the absorbed bone mar-row dose is described. In combination with the results of kidney dosimetry it is shown that 50% of the patients can tolerate more than 4 cycles of 177Lu-DOTA-octreotate without passing the so far accepted tolerance doses of 23 Gy to the kidneys and 2 Gy to the bone marrow. This implies that these pa-tients may achieve higher tumour doses when treated up to that limit.

The treatment of patients with advanced cases of colorectal NETs and bronchial carcinoids has been a clinical challenge, with very limited treat-ment options and low efficacy of available systemic treatment options. Paper III and IV present results after application of the novel methods for dosi-metry in radionuclide therapy. The results compare favourably to previously reported results of therapy in these patient groups, and the observed side effects were few. Aiming at an absorbed dose to the kidneys of 23 Gy, achieved with up to 8 cycles of 7.4 GBq of 177Lu-DOTA-octreotate at initial treatment of colorectal NETs, was associated with a longer time to progres-sion than in those that did not reach that dose at initial treatment. The limita-tions of these studies are that the some of the patients were analysed retro-spectively and not in a randomised fashion, and that more patients need to be treated to be able to draw firmer conclusions. Still, the tumour response and survival data are promising.

38

Imaging during therapy, the concept of theranostics, by using the treat-ment radionuclide as it is possible with 177Lu gives a unique insight of dy-namic changes that is impossible to achieve with any other therapy. It has been assumed in the literature that the distribution of uptake inside the tu-mour can change as an effect of previous treatment cycles resulting in a more optimal treatment situation [139] This assumption has now been sup-ported, as seen in Paper V. Increased tumour uptake and absorbed doses are shown to occur at the same time as the uptake in the spleen and bone mar-row decreases and the doses to the kidneys only increase slightly.

The results of this thesis concur in many aspects with previously published results, but there are also differences and new observations that can be high-lighted.

Peptide receptor radionuclide therapy (PRRT) directed towards somato-statin receptors has become a milestone in the treatment of NETs. It was developed in a succession of clinical achievements in the treatment of this group of tumours, leading to improved symptom control and prolonged sur-vival [83, 140-143]. It has been shown to result in morphologic response in the range of 25 to over 40% of the patients [104, 108, 109, 119, 144], with a dose dependent tumour response [145]. The reported results in this thesis are in agreement with the findings in the literature that objective responses can be achieved and that time endpoints such as overall survival and time to progression are superior in patients that reach a morphological response. On the other hand, also patients with stabilisation of a progressive disease and improved hormonal control can be considered as treatment response, as ob-served by several authors. Quality of life is an important aspect, and has been reported to improve under radionuclide therapy [120, 146]. It has not been a focus of this work, but the clinical observations in our patients are in good agreement with these findings.

Two radiopeptides have been used predominantly, 90Y-DOTATOC and 177Lu-DOTA-octreotate. Due to the different beta particle range of the radio-nuclides, it has been claimed that 90Y is a better radionuclide for larger tu-mours as opposed to 177Lu, which should be better suited for the treatment smaller lesions [102, 103, 130, 147, 148]. Tumour dosimetry in the current studies showed that 177Lu-DOTA-octreotate may be the radiopharmaceutical of choice even in large tumours. Kwekkeboom et al. report three- to fourfold higher uptake in 4 out of 5 tumours with basically unchanged uptake in kid-neys and spleen, when comparing patients treated with [177LuDOTA0Tyr3] octreotate and [111In-DTPA0] octreotide [127]. Optimal tumour-over-kidney uptake is crucial for an optimal treatment result. Taking into account the shorter tissue penetration range of 177Lu as compared to 90Y, the same group draws the conclusion that 177Lu-DOTA-octreotate is the radiolabeled soma-

39

tostatin analogue of choice for peptide receptor radiotherapy [72], which is in agreement with the discussed findings in this thesis.

Barone et al observed [149] that kidney toxicity during treatment with 90Y-DOTATOC was increased in patients with low fractionation. Their con-clusion was that kidney volumes, dose rate and fractionation play important roles for kidney dosimetry and the prediction of nephrotoxicity. The obser-vation in our present patient of an improved tumour-to-organ dose ratio as a function of previous cycles of therapy adds a new aspect to the discussion. 177Lu has in comparison to 90Y a shorter range in tissue, a lower dose rate and offers the advantage of lower irradiation of structures adjacent to the tumours. Repeated cycles of 177Lu-DOTA-octreotate may lead to improved tumour dose absorption with still acceptable kidney toxicity, if scanning and dosimetry under therapy show a more homogeneous uptake pattern in the tumour. Under these circumstances, the longer half-life of 177Lu is an ad-vantage, since the ratio of tumour-to non-tumour irradiation improves over time (Figure 12). Thus, very high, and potentially tumoricidal accumulated absorbed doses can be achieved. This pattern is frequent in colorectal NETs with a large tumour burden as they were described in Paper III. A possible contributing factor to an improved tumour uptake may be the receptor-upregulation in cells escaping from low dose radiation as observed in a ro-dent model [150, 151].

The potential for fractionated therapy with 177Lu-DOTA-octreotate in pa-tients with high tumour burden, using surveillance dosimetry should be the subject of further evaluation. A recent report comparing therapy with 90Y-DOTATATE and a combination of 90Y and 177Lu-DOTATE indicates a sur-vival advantage for the combination therapy [131]. Our reported findings suggest that a dosimetry-based approach with 177Lu-DOTA-octreotate might be advantageous over 90Y-labeled somatostatin analogues and possibly even combination therapy, and should be regarded as a veritable contestant for a randomized study, as suggested by Brans et al. in a reply to this article [152].

Figure 12

Cartoon illustrating the effect on tumour and surrounding tissues in therapy with 177Lu and 90Y. The blue ring represents the tumour uptake. The shorter range of 177Lu renders lower irradiation to adjacent tissue resulting in lower toxicity leaving the option for more treatment cycles.

The beta particle energy deposit of 90Y has a longer range outside the tumour, resulting in higher toxicity for adjacent tissues and suboptimal dose distribution in smaller tumours

40

The clinical guidelines for the treatment of poorly differentiated neuroendo-crine tumours with high proliferation rate recommend cisplatinum-based chemotherapy as first line treatment, yielding an objective response rate of 40 to 70%, with a duration of 8 to 11 months and a median survival of 15-19 months [79, 86, 153, 154]. High proliferation is generally regarded as an indicator of low somatostatin receptor expression, and somatostatin scintig-raphy is not regularly performed for this reason [154], though this recom-mendation has been changed in recent years [90]. Cisplatinum-based chemo-therapy has recently been show to have a higher response rate in tumours with a Ki-67 rate of over 55%, nevertheless, these tumours are associated with shorter survival. A study on palliative chemotherapy in poorly differen-tiated neuroendocrine carcinomas reports a median survival of 11 months for patients that received chemotherapy, compared to 1 months in patients with best supportive care [155]. Only recently, a report focusing on the results of treatment with 177Lu-octreotate in 81 patients with respect to proliferation rate found comparable outcome in patients with proliferation rates up to 20%, with partial responses in 40%, minor responses in 15% and stable dis-ease in another 34%, with 11% in progressive disease [156]. Only 2 out of 7 patients with a proliferation rate over 20% responded to the treatment that had been given in four cycles with a mean activity of 7.9 GBq at standard intervals of 3 months (10-14 weeks).

The patient reported on in Paper V, with focal Ki-67 values up to 50%, had very high somatostatin receptor expression and is at the time of the re-port 30 months progression-free after start of therapy. This underlines, that it is worthwhile to investigate somatostatin receptor expression in patients with poorly differentiated neuroendocrine carcinomas. In the small group of bronchial carcinoids reported in Paper IV, no difference in tumour response was seen in correlation to Ki-67 values. The interval between cycles ought to be of significance in highly proliferative tumours, and a shorter interval should be preferred in patients with aggressive tumour biology.

Besides kidney failure that has been predominantly seen as a side effect of 90Y-DOTATOC, bone marrow toxicity has been the other common side effect reported in association with radionuclide therapy. In Paper IV, we report on one patient that developed acute lymphatic leukemia after therapy with 177Lu-DOTA-octreotate. This is the second case of acute leukemia that occurred in patients treated with 177Lu-DOTA-octreotate at the University Hospital of Uppsala, overlooking over 340 patients treated since 2005. The here reported patient had had chemotherapy with temozolomide that had to be stopped due to bone marrow toxicity and fatigue. For the patients groups reported in this thesis, temozolomide and cisplatinum-based protocols have been the predominant first choice for systemic tumour therapy. Both the alkylator temozolomide and cisplatinum are associated with an increased risk for acute leukemia [157-159], and cisplatinum also with kidney toxicity.

41

Historical observations on women with ovarian cancers treated with alkylat-ing agents either alone or in combination with cisplatinum showed a clearly increased risk for bone marrow malignancy, that seemed to increase further if the patient also had received radiation therapy [158]. This is a fact that cannot be ignored when discussing the succession of different treatment modalities. A better understanding of the effect of low dose rate radiation may be possible when dosimetry of the bone marrow is consequently ap-plied. The suggested method renders a tool for that. The finding that bone marrow doses tend to decrease during therapy, unlike those for the kidneys, was unexpected.

The result of the bone marrow dose calculation gave at hand that in the majority of patients the kidneys were the dose-limiting organs, even if a higher dose limit of 29 Gy to the kidneys was assumed, as proposed by Konijnenberg et al [117]. This is in disagreement with the statement of Esser et al, that 70% of the patients will reach an accumulated dose of 2 Gy before the dose-limit for the kidneys is reached [160]. One explanation may be the way of calculating the cross-doses from adjacent organs and the remainder of the body. Bone marrow is highly vascularised, whereas the surrounding cortical bone contains vessels to a much smaller extent. Commonly used software programs for MIRD calculations assume that the remainder of the body includes solid bone, which means that the S-value for the calculation of cross-fire contains a beta component that is 88.7% of the total S-factor. This will most probably overestimate the bone marrow dose, which is why in the calculations presented in Paper II an S-factor without beta component is chosen. Previously, the calculation of bone marrow doses under therapy with 177Lu-DOTA-octreotate did not translate particularly well into the decrease of platelets observed [128]. A future study is planned to investigate the cor-relation between the data in the 200 patients described here and their clinical outcome.

The results reported in this thesis on colorectal NETs and bronchial car-cinoids and a case of poorly differentiated neuroendocrine cancer are prom-ising and support the view that treatment with 177Lu-DOTA-octreotate may be considered earlier in the treatment plan of the individual patient with advanced disease [123].

It has been increasingly acknowledged that dosimetry is an adjunct for optimizing the treatment protocol, to avoid side effects and increase ab-sorbed doses to tumours [161-164].

Combinations with concomitant radiosensitizing drugs have been pro-posed in order to improve the therapeutic efficacy [132-134]. Individual dosimetry can be of help in the future to tailor therapy protocols, with the goal to find the ideal time point for such combinations, with lowest risk for side effects in relation to expected tumour efficacy. The amount of unla-belled peptide has been shown influential on the tumour uptake [165]. Com-

42

binations with unlabelled peptides in optimal doses as found by pre-therapeutic examinations may in the future be used in order to optimize the outcome of radionuclide therapy with lowest possible risk for side effects [166]. The thesis concludes that dosimetry is feasible on an individual basis for patients undergoing therapy with 177Lu-DOTA-octreotate. It is a tool that can be used to improve the understanding of the effects of radionuclide therapy and to improve the therapy outcome.

43

Conclusions

Paper I For most patients it is safe to estimate the absorbed dose to the kidneys from the radionuclide uptake at 24 hours assuming an unchanged effective half-life at consecutive therapy cycles. Simplified dosimetry using this approach can serve as a tool to assess the number of treatment cycles for the individu-al patient. Patients with risk factors for kidney dysfunction and with large changes in tumour volume should be monitored more carefully. Simplified dosimetry according to this approach can serve as guidance for how many cycles of treatment a patient can tolerate.

Paper II Bone marrow dosimetry based on blood activity curves and whole body imaging is feasible. Applied together with absorbed dose calculations based on a previously published small volume-of interest method for solid organs, 197/200 patients reached accumulated doses of 23 Gy to the kidneys before the dose to the bone marrow reached 2 Gy. The described dosimetry ap-proach enabled an individually adapted therapy, in which 50 % of the pa-tients could receive more than 4 cycles of 177Lu-DOTA-octreotate with 7.4 GBq before reaching these dose limits. Dosimetry helped to avoid the under-treatment that would have resulted by using a fixed treatment schedule. Twenty percent of the patients qualified for less than 4 cycles.

Paper III and IV Dosimetry-guided, fractionated therapy with 177Lu-DOTA-octreotate aiming at an accumulated absorbed dose of 23 Gy to the kidneys is feasible, well tolerated and a favourable treatment option for patients with advanced stages of colorectal NETs as well as for patients with advanced bronchial car-cinoids. Morphological tumour response correlated positively with time to progression and overall survival.

44

Paper V The reported patient gives evidence that dosimetry-based fractionated thera-py with 177Lu-DOTA-octreotate has the potential to improve the tumour-to-tissue dose as a result of previous treatment cycles. Tumoricidal absorbed radiation doses can be achieved despite a large tumour burden and high pro-liferation rates. Imaging and dosimetry during therapy is a valuable tool for treatment planning and for the evaluation of outcome.

45

Future Perspectives

Individual dosimetry for patients undergoing peptide receptor radionuclide therapy is still in the beginning of its clinical application. A multitude of questions need to be addressed in greater detail. Amongst them are: • The maximal tolerated absorbed dose to the kidneys in the setting of

fractionated therapy with 177Lu-DOTA-octreotate is still not established and further investigations on the effect of different fractioning models are warranted.

• The relationship of absorbed dose to the bone marrow and the future risk for bone marrow malignancy, including the effect of different models of fractioning needs to be explored on an individual basis.

• Pre-therapeutic imaging to quantify the amount of somatostatin recep-tors expressed by the tumour tissue may in the future serve as a prereq-uisite to tailor the amount of administered activity in order to achieve optimal receptor saturation.

• The amount of unlabelled peptide is of importance regarding the activity uptake during therapy. Also in this case, pre-therapeutic imaging can have an important role in order to tailor the tumour-to-background ratio.

• Different types of tumours show different response patterns. Dosimetry-based protocols for slow- and fast proliferating tumours need to be de-veloped in order to optimize the risk-benefit ratio.

• Little is known about the level of absorbed tumour doses that can be reached under optimal treatment conditions. The demonstrated improved uptake pattern in later cycles of therapy with increased absorbed tumour doses in a subset of patients needs to be studied further.

• Radiosensitising agents may increase the tumour efficacy, but also the side effects of therapy with 177Lu-DOTA-octreotate. Individually per-formed dosimetry may give valuable information on achievable ab-sorbed doses to tumours and risk organs.

• Chemotherapy as well as radionuclide therapy can induce bone marrow malignancy. More data needs to be collected with respect to different tumour types in order to decide on the optimal succession of different treatments.

• Tracers for targeting of tumours other than NETs and with the same efficacy as somatostatin receptor radionuclide therapy need to be devel-oped.

46

47

Sammanfattning på svenska

Lovande resultat har erhållits i behandlingen av neuroendokrina tumörer med uttryck av somatostatinreceptorer med en peptidreceptormedierat radionuklidterapi. 177Lu-DOTA-octreotat är en av de mest använda radiopep-tiderna och standardmässsigt rekommenderas maximalt fyra behandlinscyk-ler. Mätningar av stråldosen (dosimetri) i de strålkänsligaste organen, njurar och benmärg, och själva tumören för att i stället på individnivå kunna be-stämma maximala antalet behandlingar har hittills bedömts som svårt att genomföra regelmässigt.

Det första målet med denna avhandling var att utveckla ett kliniskt tillämp-ningsbart protokoll för beräkningen av den absorberade stråldosen i benmärg och njurar under behandling med 177Lu-DOTA-octreotat. Dosimetri för or-gan baserat på tre-dimensionell avbildning har tidigare beskrivits av forskar-gruppen, och ett nytt protokoll för benmärgs-dosimetri utvecklades. Hos de flesta patienter hittades bara små förändringar av den effektiva halveringsti-den in njurarna under loppet av behandlingarna. Komplett dosimetri under första cykeln jämfört med mätningar under senare cykler visade att den ab-sorberade dosen kan beräknas baserat på aktivitetskoncentrationen ett dygn efter start av varje behandlingscykel. Studiens slutsats var att den rådande behandlingsstandarden leder till suboptimal behandling av en majoritet av patienterna: 50% av alla patienter kunde få fler än fyra behandlingscykler med 7,4 GBq 177Lu-DOTA-octreotat utan att överskrida gränsvärdet av 23 Gray till njurarna eller 2 Gray till benmärgen, och för 20% av patienterna var fyra behandlingscykler för mycket.

Avhandlingens andra mål var att utvärdera resultatet av en dosimetristyrd behandling med 177Lu-DOTA-octreotat. i patientgrupper med olika typer av neuroendokrina tumörer. Patienter med utspridda tumörer från änd-och tjocktarm respektive från luftrör och lunga visade sig ha längre överlevnad med denna metod jämfört med tidigare studier och med andra behandlingar. Vidare fanns ett samband mellan minskningen av tumörstorleken och tid fram till tumörprogress. Dessutom visades i ett fall av neuroendokrin cancer att även stora och snabbväxande tumörer kan behandlas med denna metod. I detta fall ökade dosen i tumörerna vid senare behandlingar men inte i friska organ, vilket ledde till en ännu bättre terapeutisk effekt under senare cykler.

48

Dosimetri-ledd, fraktionerad radionuklidbehandling med 177Lu-DOTA-octreotat är en värdefull behandlingsmöjlighet för patienter med avancerade neuroendokrina tumörer som uttrycker somatostatinreceptorer.

49

Zusammenfassung auf Deutsch

Die Peptidrezeptor vermittelte Radionuklidbehandlung zur inneren Strahlen-behandlung von neuroendokrinen Tumoren hat große Fortschritte gemacht und weist vielversprechende Ergebnisse auf. 177Lu-DOTA-octreotat ist eines der meist verwendeten Radiopeptide. Bisher war man der Ansicht, dass Me-thoden zur Messung der Strahlendosis (Dosimetrie) für sowohl die Risiko-organe Nieren und Knochenmark, als auch für Tumoren in einzelnen Patien-ten praktisch nicht durchführbar waren. Stattdessen wurde in den meisten Fällen eine Standardbehandlung mit vier Behandlungszyklen à 7,4 GBq durchgeführt.

Das erste Ziel diese Arbeit war es, ein klinisch durchführbares Protokoll zur Berechnung der absorbierten Strahlendosis in Knochenmark und Nieren für Patienten unter Behandlung mit 177Lu-DOTA-octreotat zu entwickeln. Die Dosimetrie von soliden Organen auf der Basis von dreidimensioneller Bild-gebung zu mehreren Zeitpunkten nach der Behandlung war bereits von unse-rer Forschergruppe beschrieben worden. Ein neues Dosimetrieprotokoll für das Knochenmark wurde erstellt. Es zeigte sich, dass sich in den meisten Fällen die effektive Halbwertszeit in den Nieren nur wenig veränderte. In-dem man eine komplette Dosimetrie während des ersten Zyklus durchführte und das Ergebnis mit einer Aufnahme nach 24 Stunden in späterer Zyklen verglich, konnte man zeigen, dass die absorbierte Strahlendosis aufgrund der Aktivitätskonzentration zu diesem Zeitpunkt berechnet werden kann. Die Studie kam zu dem Schluss, dass die bisherige Standardbehandlung für den Grossteil der Patienten nicht adäquat ist: 50% der Patienten konnten mehr als die vier üblichen Zyklen mit 7,4 GBq 177Lu-DOTA-octreotat bekommen, ohne dass der Grenzwert von 23 Gray für die Nieren und 2 Gray für das Knochenmark überschritten wurde, dagegen konnten 20% der Patienten nur weniger als vier Behandlungszyklen tolerieren.

Das zweite Ziel der Arbeit war die Beschreibung von Ergebnissen einer dosimetrie-gesteuerten Behandlung mit 177Lu-DOTA-octreotat. Man konnte zeigen, dass Patienten mit metastasierten colorektalen neuroendokrinen Tu-moren und Bronchialkarzinoiden mit dieser Methode längere Überlebenszei-ten hatten als mit anderen Behandlungsmethoden. Je besser der Behand-lungseffekt auf die Tumoren war, desto längere Zeit verging bis die Tumo-

50

ren wieder anfingen zu wachsen. Darüber hinaus konnte an einem Patientfall mit einem niedrig differenzierten neuroendokrinen Tumor gezeigt werden, dass auch große Tumoren mit hoher Zuwachsrate erfolgreich mit dieser Me-thode behandelt werden können und dass sich im Laufe der Behandlung das Verhältnis zwischen Bestrahlung von Tumoren und Risikoorganen verbes-sern kann, was zu einer effektiveren Behandlung führte.

Dosimetrie-geleitete, fraktionierte Radionuklidbehandlung mit 177Lu-DOTA-octreotat ist eine wertvolle Behandlungsoption für Patienten mit fortgeschrit-tener Erkrankung an neuroendokrinen Tumoren, die Somatostatinrezeptoren ausdrücken.

51

Acknowledgments

Many people have contributed for this thesis to happen. It is an honour and pleasure to thank you all.

My supervisors Barbro Eriksson, Anders Sundin, Göran Hedenstierna and Jens Sörensen: You gave me the opportunity to study this interesting and evolving field, to think freely and to grow. I am very grateful.

Hans Lundqvist: Thank you for “adopting” me, sharing your vast knowledge and your humour, giving me time for reflections on science and life. Jörgen Carlsson: Thank you for sharing you knowledge on science and teaching, and thank you for making me feel smarter than I am- I needed it! Christer Sundström and Lars Grimelius: Thank you for being my supervisors when I arrived-very young and inexperienced-to Sweden. You were so kind and hospitable, you shared your deep knowledge generously, and you meant so much for getting to the place I am now. Jan Erik Westlin and Sten Nilsson: You introduced me to the field of target-ed radionuclide therapy. It has been so much fun and a real privilege to work with you! My co-authors Mattias Sandström, Dan Granberg, Silvia Johansson, Per Hellman, Staffan Welin, Katarzyna Fröss Baron, Pantelis Antonomitridiakis, Joakim Crona, Daniel Lindholm och Mark Lubberink: Thank you for good and enjoyable discussions, critical and fun arguments. I hope we keep on working together for a long time to come! My colleagues and friends at the different departments of Akademiska Sju-khuset I work and have worked with through the years in Nuclear Medicine, Clinical Physiology, Radiology, Endocrine Oncology, Oncology, Hematolo-gy, Pediatric Oncology and Pathology: Lars Göran, Tanja, Cecilia, Catrin, Kamelia, Dan, Hans, Staffan, Margareta, Bertil, Torsten, Madis, Apostolos, Henrik, Gordana, Eva, Anders G, Ulla, Gunilla, Bengt, Kjell, Kristina, Gun-nar, Susan, Fredrik, Johan and many, many others of you that have shared

52

your insights, kindness and professional advice: You make my day, every day! The staff at the Nuclear Medicine and Endocrine Oncology: (In no particular order) Anna, Cissi, Pia, Eva, Annika, Ann-Christine, Camilla, Birgitta, Fad-hiya, Marie, Mirtha, Afroza, Fredrik, Hedy, Lena, Rahaf, Riselda, Katharina and all other new and old colleagues: It means so much to see your friendly smile and feel your professional attitude every day! Madina, Ewa, Jolanta and Aseel at the Radiopharmaceutical Lab: You are not only professional and knowledgeable, but you are also kind and nice: What a combination! Charles, Anna, Enn and Anders from Hospital Physics: It feels safe to have your support and wise comments at hand, for big and small problems- you have the solution! Thank you for all help and your cheerful attitude! Mats Rynnes: No matter how little time you have- you always help, and you always smile! Thank you! My bosses and former bosses Adel Shalabi, Per Eckerbom and Per Liss: Thank you for giving me the space and trusting me with my task. All secretaries, that helped and supported and were kind to me through the years, even if I did not always deserve it: Didde, Maria, Gabbis, Monkan, Kicki, Maria, Inger, Annette: Thank you! My colleagues and friends at the Rudbeck laboratory and the PET center: Anna and Vladimir (“Pierre et Marie”), Marika Nestor, Bo Stenerlöw, Lars Gedda, Mimmi and your colleagues at PET-center: Research is so much more fun with all your good support and wise comments: Thank you! My friends: Gertrud and Björn: Thank you for being such an inspiration! We want to be like you when we grow up!

Irina Savitcheva and Vladimir: Thank you for being our friends and Irina for being my “roomy” and all the good discussions on everything that moves us! Irina Velikyan and Misha: Thank you for being our friends, you are so much fun and so spiritual!

53

My Swedish friends Cecilia, Gunilla, Karin, Suzanne: You are my Swedish back-up, taught me the Swedish ways and the Swedish language- Thank you for all the fun, the laughter and all deep and less deep discussions! Ia och Ulf: Våra svenska grannar och support- tack för att ni är så snälla mot Milton och mig! Mandy Trickett: Many thanks for your skillful linguistic revision of the ma-nuscripts and you cheerful comments!

My childhood friends Ingrid with Manuel, Lara and Louisa, Ulrike und Claudia: Ihr seid meine Brücke zu meinen Wurzeln: Danke, dass es Euch gibt! Iris und Stefan mit Sarah, Jasmin und Nora: Ihr seid meine Wahlfamilie- Danke für die vielen guten Erinnerungen an Wohngemeinschaftszeiten, die Unterstützung in allen wichtigen und weniger wichtigen Dingen und für den Spass den wir zusammen gehabt haben und hoffentlich noch haben werden! Conni: Unbesehen was in unseren Leben passiert ist- wir haben den Kontakt behalten! Danke für deine Freundschaft und schöne Erinnerungen an unsere gemeinsamen Backorgien! My New Zealand friends: Ted and Jeanette, Caroline: Thank you for your friendship, good conversations and for sharing your beautiful country with me! Tijana, Björn och Maja: Ni gav mig en av anledningarna att stanna kvar i Sverige: Tack för att ni är våra vänner! Aili and Ulf mit John, Emma und Linn: Ihr seid zu gut um wahrzusein! Tack, Danke, Thank you, Gracias für Eure Freundschaft, Unterstützung und unendliche leckere Kuchen! Meine Familie: Meine Schwester Barbara mit Georg, Maren und Henning und mein Bruder Lothar mit Veronica und Moritz: Ihr seid die beste Familie, die ich mir wünschen kann! Mi nueva familia en Costa Rica y Curaçao: mi suegra Alicia y mi cuñado Eri, con Grettel, Tania, Allan y Erik y mi cuñado Fito, con sus hijos: Muchas

54

gracias! (-I promise to learn more Spanish, to tell you how grateful I am that you have welcomed me into your family!) Meine Eltern Anna und Johannes: Danke, dass Ihr mich mit so viel Liebe, Humor und Gottvertrauen habt aufwachsen lassen. Ich hab Euch lieb! Anouk och Alicia: Ihr seid wunderbar! Ni är fantastiska! Milton: Thank you for giving me the ground to stand on, for your love, jokes and energy, and for bringing the colour to my life. I love you.

55

References

1. Modlin, I.M., K.D. Lye, and M. Kidd, A 5-decade analysis of 13,715 carcinoid tumors. Cancer, 2003. 97(4): p. 934-59.

2. Hauso, O., et al., Neuroendocrine tumor epidemiology: contrasting Norway and North America. Cancer, 2008. 113(10): p. 2655-64.

3. Modlin, I.M., et al., A three-decade analysis of 3,911 small intestinal neuroendocrine tumors: the rapid pace of no progress. Am J Gastroenterol, 2007. 102(7): p. 1464-73.

4. Gustafsson, B.I., et al., Bronchopulmonary neuroendocrine tumors. Cancer, 2008. 113(1): p. 5-21.

5. Modlin, I.M., et al., Gastroenteropancreatic neuroendocrine tumours. Lancet Oncol, 2008. 9(1): p. 61-72.

6. Halfdanarson, T.R., et al., Pancreatic neuroendocrine tumors (PNETs): incidence, prognosis and recent trend toward improved survival. Ann Oncol, 2008. 19(10): p. 1727-33.

7. Ruszniewski, P. and B. Terris, [Natural history and prognosis of pancreatic endocrine tumors]. Gastroenterol Clin Biol, 2003. 27(3 Suppl): p. S20-5.

8. Oberg, K. and B. Eriksson, Endocrine tumours of the pancreas. Best Pract Res Clin Gastroenterol, 2005. 19(5): p. 753-81.

9. Merling, F., Anatomie pathologique de l' appendice du caecum. Experience, 1838. 1: p. 337.

10. Klöppel, G., Oberndorfer and his successors: From Carcinoid to Neuroendocrine Carcinoma. Endocr Pathol, 2007. 18: p. 141-144.

11. Oberndorfer, S., Karzinoide Tumoren des Dünndarms. Frankf Z Pathol 1907. 1: p. 425-432.

12. Oberndorfer, S., Ueber die "kleinen Dünndarmcarcinome". Verh Dtsch Ges Pathol, 1907. 11: p. 113-116.

13. Oberndorfer, S., Die Geschwülste des Darms. In Henke, F, Lubarsch, O (eds). Handbuch der speziellen pathologischen Anatomie und Histologie, Springer (Berlin), 1929. 4(3 Verdauungsschlauch): p. 717-953.

14. Hellerstroem, C. and B. Hellman, Some aspects of silver impregnation of the islets of Langerhans in the rat. Acta Endocrinol (Copenh), 1960. 35: p. 518-32.

15. Polak, J.M., et al., Growth-hormone release-inhibiting hormone in gastrointestinal and pancreatic D cells. Lancet, 1975. 1(7918): p. 1220-2.

16. Hokfelt, T., et al., Cellular localization of somatostatin in endocrine-like cells and neurons of the rat with special references to the A1-cells of the pancreatic islets and to the hypothalamus. Acta Endocrinol Suppl (Copenh), 1975. 200: p. 5-41.

17. Masson, P., La glande endocrine de l'intestin chez l'homme. C R Acad Sci (Paris), 1914. 138: p. 59-61.

18. Grimelius, L., A silver nitrate stain for alpha-2 cells in human pancreatic islets. Acta Soc Med Ups, 1968. 73(5-6): p. 243-70.

19. Grimelius, L. and E. Wilander, Silver stains in the study of endocrine cells of the gut and pancreas. Invest Cell Pathol, 1980. 3(1): p. 3-12.

56

20. Grimelius, L., Silver stains demonstrating neuroendocrine cells. Biotech Histochem, 2004. 79(1): p. 37-44.

21. Wilander, E., et al., Argentaffin and argyrophil reactions of human gastrointestinal carcinoids. Gastroenterology, 1977. 73(4 Pt 1): p. 733-6.

22. Gazdar, A.F., et al., Expression of neuroendocrine cell markers L-dopa decarboxylase, chromogranin A, and dense core granules in human tumors of endocrine and nonendocrine origin. Cancer Res, 1988. 48(14): p. 4078-82.

23. Eriksson, B., et al., Chromogranins--new sensitive markers for neuroendocrine tumors. Acta Oncol, 1989. 28(3): p. 325-9.

24. McFerran, B.W., M.E. Graham, and R.D. Burgoyne, Neuronal Ca2+ sensor 1, the mammalian homologue of frequenin, is expressed in chromaffin and PC12 cells and regulates neurosecretion from dense-core granules. J Biol Chem, 1998. 273(35): p. 22768-72.

25. Feyrter, F., Karzinoid und Karzinom. Ergebn Allg Pathol Anat, 1934. 29: p. 305-489.

26. Feyrter, F., Über diffuse endokrine epitheliale Organe. J.A.Barth, Leipzig, 1938.

27. Feyrter, F., [A morphologic principle of central and peripheral endocrine regulation]. Klin Wochenschr, 1950. 28(31-32): p. 533-5.

28. Champaneria, M.C., et al., Friedrich Feyrter: a precise intellect in a diffuse system. Neuroendocrinology, 2006. 83(5-6): p. 394-404.

29. Pearse, A.G., The cytochemistry and ultrastructure of polypeptide hormone-producing cells of the APUD series and the embryologic, physiologic and pathologic implications of the concept. J Histochem Cytochem, 1969. 17(5): p. 303-13.

30. Garcia-Carbonero, R., et al., Incidence, patterns of care and prognostic factors for outcome of gastroenteropancreatic neuroendocrine tumors (GEP-NETs): results from the National Cancer Registry of Spain (RGETNE). Ann Oncol, 2010. 21(9): p. 1794-803.

31. Modlin, I.M., et al., Current status of gastrointestinal carcinoids. Gastroenterology, 2005. 128(6): p. 1717-51.

32. Williams, E.D., Sandler, M., The classification of carcinoid tumours. The Lancet, 1963. 1: p. 238-239.

33. Ransom, W.B., A case of primary carcinoma of the ileum. Lancet, 1890. ii: p. 1020-1023.

34. Cassidy, M.A., Post-mortem Findings in Case Shown on October 10, 1930, as one of Abdominal Carcinomatosis with Probable Adrenal Involvement. Proc R Soc Med, 1931. 24(7): p. 920-1.

35. Scholte, A.J., Ein Fall von Angioma teleangiectaticum Cutis mit chronischer Endocarditis und malignem Dünndarmcarcinoid. Beitr Pathol 1931. 86: p. 440-443.

36. Isler, P. and C. Hedinger, [Metastatic carcinoid of the small intestine with severe valvular defects especially in the right part of the heart and with pulmonary stenosis; a peculiar symptom complex]. Schweiz Med Wochenschr, 1953. 83(1): p. 4-7.

37. Eriksson, B., et al., Consensus guidelines for the management of patients with digestive neuroendocrine tumors--well-differentiated jejunal-ileal tumor/carcinoma. Neuroendocrinology, 2008. 87(1): p. 8-19.

38. Proye, C., Natural history of liver metastasis of gastroenteropancreatic neuroendocrine tumors: place for chemoembolization. World J Surg, 2001. 25(6): p. 685-8.

57

39. Janson, E.T., et al., Carcinoid tumors: analysis of prognostic factors and survival in 301 patients from a referral center. Ann Oncol, 1997. 8(7): p. 685-90.

40. Oberg, K., Neuroendocrine gastrointestinal tumours. Ann Oncol, 1996. 7(5): p. 453-63.

41. Wieland, D.M., et al., Imaging the adrenal medulla with an I-131-labeled antiadrenergic agent. J Nucl Med, 1979. 20(2): p. 155-8.

42. Allan, I.J. and D.F. Newgreen, Catecholamine accumulation in neural crest cells and the primary sympathetic chain. Am J Anat, 1977. 149(3): p. 413-21.

43. Hoefnagel, C.A., et al., Total-body scintigraphy with 131I-meta-iodobenzylguanidine for detection of neuroblastoma. Diagn Imaging Clin Med, 1985. 54(1): p. 21-7.

44. Hoefnagel, C.A., Metaiodobenzylguanidine and somatostatin in oncology: role in the management of neural crest tumours. Eur J Nucl Med, 1994. 21(6): p. 561-81.

45. Mukherjee, J.J., et al., Treatment of metastatic carcinoid tumours, phaeochromocytoma, paraganglioma and medullary carcinoma of the thyroid with (131)I-meta-iodobenzylguanidine [(131)I-mIBG]. Clin Endocrinol (Oxf), 2001. 55(1): p. 47-60.

46. Kaltsas, G., et al., Comparison of somatostatin analog and meta-iodobenzylguanidine radionuclides in the diagnosis and localization of advanced neuroendocrine tumors. J Clin Endocrinol Metab, 2001. 86(2): p. 895-902.

47. Ezziddin, S., et al., Factors predicting tracer uptake in somatostatin receptor and MIBG scintigraphy of metastatic gastroenteropancreatic neuroendocrine tumors. J Nucl Med, 2006. 47(2): p. 223-33.

48. Rosenspire, K.C., et al., Synthesis and preliminary evaluation of carbon-11-meta-hydroxyephedrine: a false transmitter agent for heart neuronal imaging. J Nucl Med, 1990. 31(8): p. 1328-34.

49. Shulkin, B.L., et al., PET scanning with hydroxyephedrine: an approach to the localization of pheochromocytoma. J Nucl Med, 1992. 33(6): p. 1125-31.

50. Shulkin, B.L., et al., PET hydroxyephedrine imaging of neuroblastoma. J Nucl Med, 1996. 37(1): p. 16-21.

51. Trampal, C., et al., Pheochromocytomas: detection with 11C hydroxyephedrine PET. Radiology, 2004. 230(2): p. 423-8.

52. Buursma, A.R., et al., The human norepinephrine transporter in combination with 11C-m-hydroxyephedrine as a reporter gene/reporter probe for PET of gene therapy. J Nucl Med, 2005. 46(12): p. 2068-75.

53. Hennings, J., et al., Computed tomography, magnetic resonance imaging and 11C-metomidate positron emission tomography for evaluation of adrenal incidentalomas. Eur J Radiol, 2009. 69(2): p. 314-23.

54. Hennings, J., et al., [11C]metomidate positron emission tomography of adrenocortical tumors in correlation with histopathological findings. J Clin Endocrinol Metab, 2006. 91(4): p. 1410-4.

55. Hennings, J., et al., 11C-metomidate positron emission tomography after dexamethasone suppression for detection of small adrenocortical adenomas in primary aldosteronism. Langenbecks Arch Surg, 2010. 395(7): p. 963-7.

56. Ahlstrom, H., et al., Pancreatic neuroendocrine tumors: diagnosis with PET. Radiology, 1995. 195(2): p. 333-7.

58

57. Bergstrom, M., et al., In vivo demonstration of enzyme activity in endocrine pancreatic tumors: decarboxylation of carbon-11-DOPA to carbon-11-dopamine. J Nucl Med, 1996. 37(1): p. 32-7.

58. Orlefors, H., et al., Positron emission tomography with 5-hydroxytryprophan in neuroendocrine tumors. J Clin Oncol, 1998. 16(7): p. 2534-41.

59. Sundin, A., et al., Demonstration of [11C] 5-hydroxy-L-tryptophan uptake and decarboxylation in carcinoid tumors by specific positioning labeling in positron emission tomography. Nucl Med Biol, 2000. 27(1): p. 33-41.

60. Orlefors, H., et al., Whole-body (11)C-5-hydroxytryptophan positron emission tomography as a universal imaging technique for neuroendocrine tumors: comparison with somatostatin receptor scintigraphy and computed tomography. J Clin Endocrinol Metab, 2005. 90(6): p. 3392-400.

61. Krenning, E.P., et al., Localisation of endocrine-related tumours with radioiodinated analogue of somatostatin. Lancet, 1989. 1(8632): p. 242-4.

62. Krenning, E.P., et al., Somatostatin receptor scintigraphy with indium-111-DTPA-D-Phe-1-octreotide in man: metabolism, dosimetry and comparison with iodine-123-Tyr-3-octreotide. J Nucl Med, 1992. 33(5): p. 652-8.

63. Krenning, E.P., et al., Somatostatin-receptor scintigraphy in gastroenteropancreatic tumors. An overview of European results. Ann N Y Acad Sci, 1994. 733: p. 416-24.

64. Krenning, E.P., et al., Somatostatin receptor scintigraphy in carcinoids, gastrinomas and Cushing's syndrome. Digestion, 1994. 55 Suppl 3: p. 54-9.

65. Krenning, E.P., et al., Somatostatin receptor scintigraphy with [111In-DTPA-D-Phe1]- and [123I-Tyr3]-octreotide: the Rotterdam experience with more than 1000 patients. Eur J Nucl Med, 1993. 20(8): p. 716-31.

66. Sundin, A., U. Garske, and H. Orlefors, Nuclear imaging of neuroendocrine tumours. Best Pract Res Clin Endocrinol Metab, 2007. 21(1): p. 69-85.

67. Gabriel, M., et al., An intrapatient comparison of 99mTc-EDDA/HYNIC-TOC with 111In-DTPA-octreotide for diagnosis of somatostatin receptor-expressing tumors. J Nucl Med, 2003. 44(5): p. 708-16.

68. Gabriel, M., et al., 99mTc-EDDA/HYNIC-Tyr(3)-octreotide for staging and follow-up of patients with neuroendocrine gastro-entero-pancreatic tumors. Q J Nucl Med Mol Imaging, 2005. 49(3): p. 237-44.

69. Gabriel, M., et al., 68Ga-DOTA-Tyr3-octreotide PET in neuroendocrine tumors: comparison with somatostatin receptor scintigraphy and CT. J Nucl Med, 2007. 48(4): p. 508-18.

70. Kayani, I., et al., Functional imaging of neuroendocrine tumors with combined PET/CT using 68Ga-DOTATATE (DOTA-DPhe1,Tyr3-octreotate) and 18F-FDG. Cancer, 2008. 112(11): p. 2447-55.

71. Luboldt, W., et al., Gastroenteropancreatic Neuroendocrine Tumors: Standardizing Therapy Monitoring with 68Ga-DOTATOC PET/CT Using the Example of Somatostatin Receptor Radionuclide Therapy. Mol Imaging, 2010. 9(6): p. 351-358.

72. Kwekkeboom, D.J., et al., Somatostatin-receptor-based imaging and therapy of gastroenteropancreatic neuroendocrine tumors. Endocr Relat Cancer, 2010. 17(1): p. R53-73.

73. Akerstrom, G. and P. Hellman, Surgical aspects of neuroendocrine tumours. Eur J Cancer, 2009. 45 Suppl 1: p. 237-50.

74. Hellman, P., et al., Surgical strategy for large or malignant endocrine pancreatic tumors. World J Surg, 2000. 24(11): p. 1353-60.

59

75. Hellman, P., et al., Effect of surgery on the outcome of midgut carcinoid disease with lymph node and liver metastases. World J Surg, 2002. 26(8): p. 991-7.

76. Akerstrom, G., et al., ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Tumors: pre- and perioperative therapy in patients with neuroendocrine tumors. Neuroendocrinology, 2009. 90(2): p. 203-8.

77. Hellman, P., et al., Stenting of the superior mesenteric vein in midgut carcinoid disease with large mesenteric masses. World J Surg, 2010. 34(6): p. 1373-9.

78. Zagar, T.M., et al., Resected pancreatic neuroendocrine tumors: patterns of failure and disease-related outcomes with or without radiotherapy. Int J Radiat Oncol Biol Phys, 2012. 83(4): p. 1126-31.

79. Janson, E.T., et al., Nordic Guidelines 2010 for diagnosis and treatment of gastroenteropancreatic neuroendocrine tumours. Acta Oncol, 2010. 49(6): p. 740-56.

80. Reubi, J.C., et al., Somatostatin receptors in malignant tissues. J Steroid Biochem Mol Biol, 1990. 37(6): p. 1073-7.

81. Reubi, J.C., Somatostatin and other Peptide receptors as tools for tumor diagnosis and treatment. Neuroendocrinology, 2004. 80 Suppl 1: p. 51-6.

82. Wymenga, A.N., et al., Efficacy and safety of prolonged-release lanreotide in patients with gastrointestinal neuroendocrine tumors and hormone-related symptoms. J Clin Oncol, 1999. 17(4): p. 1111.

83. Kvols, L.K., et al., The presence of somatostatin receptors in malignant neuroendocrine tumor tissue predicts responsiveness to octreotide. Yale J Biol Med, 1992. 65(5): p. 505-18; discussion 531-6.

84. Moertel, C.G., J.A. Hanley, and L.A. Johnson, Streptozocin alone compared with streptozocin plus fluorouracil in the treatment of advanced islet-cell carcinoma. N Engl J Med, 1980. 303(21): p. 1189-94.

85. Delaunoit, T., et al., The doxorubicin-streptozotocin combination for the treatment of advanced well-differentiated pancreatic endocrine carcinoma; a judicious option? Eur J Cancer, 2004. 40(4): p. 515-20.

86. Ramage, J.K., et al., Guidelines for the management of gastroenteropancreatic neuroendocrine (including carcinoid) tumours (NETs). Gut, 2012. 61(1): p. 6-32.

87. Ekeblad, S., et al., Temozolomide as monotherapy is effective in treatment of advanced malignant neuroendocrine tumors. Clin Cancer Res, 2007. 13(10): p. 2986-91.

88. Arnold, R., et al., Endocrine tumours of the gastrointestinal tract: Chemotherapy. Best Pract Res Clin Gastroenterol, 2005. 19(4): p. 649-56.

89. Caplin, M., et al., ENETS Consensus Guidelines for the management of patients with digestive neuroendocrine neoplasms: colorectal neuroendocrine neoplasms. Neuroendocrinology, 2012. 95(2): p. 88-97.

90. Oberg, K., et al., Neuroendocrine bronchial and thymic tumours: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol, 2010. 21 Suppl 5: p. v220-2.

91. Granberg, D., et al., Experience in treatment of metastatic pulmonary carcinoid tumors. Ann Oncol, 2001. 12(10): p. 1383-91.

92. Wirth, L.J., et al., Outcome of patients with pulmonary carcinoid tumors receiving chemotherapy or chemoradiotherapy. Lung Cancer, 2004. 44(2): p. 213-20.

60

93. Lindholm, D.P., Fanola, I., Eriksson, B., Granberg, D., Temozolomide in Patients with Metastatic Bronchial Carcinoids, in 14th World Conference on Lung Cancer (WCLC 2011) 2011: Amsterdam.

94. Ahlman, H., et al., Poorly-differentiated endocrine carcinomas of midgut and hindgut origin. Neuroendocrinology, 2008. 87(1): p. 40-6.

95. Welin, S., et al., Clinical effect of temozolomide-based chemotherapy in poorly differentiated endocrine carcinoma after progression on first-line chemotherapy. Cancer, 2011. 117(20): p. 4617-22.

96. Fjallskog, M.L., et al., Treatment with cisplatin and etoposide in patients with neuroendocrine tumors. Cancer, 2001. 92(5): p. 1101-7.

97. Granberg, D., Investigational drugs for neuroendocrine tumours. Expert Opin Investig Drugs, 2009. 18(5): p. 601-8.

98. Valkema, R., et al., Phase I study of peptide receptor radionuclide therapy with [In-DTPA]octreotide: the Rotterdam experience. Semin Nucl Med, 2002. 32(2): p. 110-22.

99. Kwekkeboom, D.J., et al., Overview of results of peptide receptor radionuclide therapy with 3 radiolabeled somatostatin analogs. J Nucl Med, 2005. 46 Suppl 1: p. 62S-6S.

100. De Jong, M., et al., Therapy of neuroendocrine tumors with radiolabeled somatostatin-analogues. Q J Nucl Med, 1999. 43(4): p. 356-66.

101. Anthony, L.B., et al., Indium-111-pentetreotide prolongs survival in gastroenteropancreatic malignancies. Semin Nucl Med, 2002. 32(2): p. 123-32.

102. O'Donoghue, J.A., M. Bardies, and T.E. Wheldon, Relationships between tumor size and curability for uniformly targeted therapy with beta-emitting radionuclides. J Nucl Med, 1995. 36(10): p. 1902-9.

103. de Jong, M., et al., [177Lu-DOTA(0),Tyr3] octreotate for somatostatin receptor-targeted radionuclide therapy. Int J Cancer, 2001. 92(5): p. 628-33.

104. Waldherr, C., et al., Tumor response and clinical benefit in neuroendocrine tumors after 7.4 GBq (90)Y-DOTATOC. J Nucl Med, 2002. 43(5): p. 610-6.

105. Bodei, L., et al., Receptor-mediated radionuclide therapy with 90Y-DOTATOC in association with amino acid infusion: a phase I study. Eur J Nucl Med Mol Imaging, 2003. 30(2): p. 207-16.

106. Valkema, R., et al., Survival and response after peptide receptor radionuclide therapy with [90Y-DOTA0,Tyr3]octreotide in patients with advanced gastroenteropancreatic neuroendocrine tumors. Semin Nucl Med, 2006. 36(2): p. 147-56.

107. Otte, A., et al., Yttrium-90 DOTATOC: first clinical results. Eur J Nucl Med, 1999. 26(11): p. 1439-47.

108. Chinol, M., et al., Receptor-mediated radiotherapy with Y-DOTA-DPhe-Tyr-octreotide: the experience of the European Institute of Oncology Group. Semin Nucl Med, 2002. 32(2): p. 141-7.

109. Imhof, A., et al., Response, survival, and long-term toxicity after therapy with the radiolabeled somatostatin analogue [90Y-DOTA]-TOC in metastasized neuroendocrine cancers. J Clin Oncol, 2011. 29(17): p. 2416-23.

110. Kwekkeboom, D.J., et al., Peptide receptor radionuclide therapy in patients with gastroenteropancreatic neuroendocrine tumors. Semin Nucl Med, 2010. 40(2): p. 78-88.

111. Schumacher, T., et al., Kidney failure after treatment with 90Y-DOTATOC. Eur J Nucl Med Mol Imaging, 2002. 29(3): p. 435.

61

112. Valkema, R., et al., Long-term follow-up of renal function after peptide receptor radiation therapy with (90)Y-DOTA(0),Tyr(3)-octreotide and (177)Lu-DOTA(0), Tyr(3)-octreotate. J Nucl Med, 2005. 46 Suppl 1: p. 83S-91S.

113. Rolleman, E.J., et al., Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues. Eur J Nucl Med Mol Imaging, 2010. 37(5): p. 1018-31.

114. Rolleman, E.J., et al., Safe and effective inhibition of renal uptake of radiolabelled octreotide by a combination of lysine and arginine. Eur J Nucl Med Mol Imaging, 2003. 30(1): p. 9-15.

115. De Jong, M., et al., Pre-clinical comparison of [DTPA0] octreotide, [DTPA0,Tyr3] octreotide and [DOTA0,Tyr3] octreotide as carriers for somatostatin receptor-targeted scintigraphy and radionuclide therapy. Int J Cancer, 1998. 75(3): p. 406-11.

116. Reubi, J.C., et al., Affinity profiles for human somatostatin receptor subtypes SST1-SST5 of somatostatin radiotracers selected for scintigraphic and radiotherapeutic use. Eur J Nucl Med, 2000. 27(3): p. 273-82.

117. Konijnenberg, M., et al., Radiation dose distribution in human kidneys by octreotides in peptide receptor radionuclide therapy. J Nucl Med, 2007. 48(1): p. 134-42.

118. Kwekkeboom, D.J., et al., Treatment of patients with gastro-entero-pancreatic (GEP) tumours with the novel radiolabelled somatostatin analogue [177Lu-DOTA(0),Tyr3]octreotate. Eur J Nucl Med Mol Imaging, 2003. 30(3): p. 417-22.

119. Kwekkeboom, D.J., et al., Treatment with the radiolabeled somatostatin analog [177 Lu-DOTA 0,Tyr3]octreotate: toxicity, efficacy, and survival. J Clin Oncol, 2008. 26(13): p. 2124-30.

120. Kam, B.L., et al., Lutetium-labelled peptides for therapy of neuroendocrine tumours. Eur J Nucl Med Mol Imaging, 2012.

121. Bodei, L., et al., Yttrium-labelled peptides for therapy of NET. Eur J Nucl Med Mol Imaging, 2012. 39 Suppl 1: p. S93-102.

122. Emami, B., et al., Tolerance of normal tissue to therapeutic irradiation. Int J Radiat Oncol Biol Phys, 1991. 21(1): p. 109-22.

123. Kwekkeboom, D.J., et al., Radiolabeled somatostatin analog [177Lu-DOTA0,Tyr3]octreotate in patients with endocrine gastroenteropancreatic tumors. J Clin Oncol, 2005. 23(12): p. 2754-62.

124. Wehrmann, C., et al., Results of individual patient dosimetry in peptide receptor radionuclide therapy with 177Lu DOTA-TATE and 177Lu DOTA-NOC. Cancer Biother Radiopharm, 2007. 22(3): p. 406-16.

125. De Jong, M., et al., Somatostatin receptor-targeted radionuclide therapy of tumors: preclinical and clinical findings. Semin Nucl Med, 2002. 32(2): p. 133-40.

126. Sandstrom, M., et al., Individualized dosimetry in patients undergoing therapy with (177)Lu-DOTA-D-Phe (1)-Tyr (3)-octreotate. Eur J Nucl Med Mol Imaging, 2010. 37(2): p. 212-25.

127. Kwekkeboom, D.J., et al., [177Lu-DOTAOTyr3]octreotate: comparison with [111In-DTPAo]octreotide in patients. Eur J Nucl Med, 2001. 28(9): p. 1319-25.

128. Forrer, F., et al., Bone marrow dosimetry in peptide receptor radionuclide therapy with [177Lu-DOTA(0),Tyr(3)]octreotate. Eur J Nucl Med Mol Imaging, 2009. 36(7): p. 1138-46.

62

129. van Essen, M., et al., Salvage therapy with (177)Lu-octreotate in patients with bronchial and gastroenteropancreatic neuroendocrine tumors. J Nucl Med, 2010. 51(3): p. 383-90.

130. de Jong, M., et al., Combination radionuclide therapy using 177Lu- and 90Y-labeled somatostatin analogs. J Nucl Med, 2005. 46 Suppl 1: p. 13S-7S.

131. Kunikowska, J., et al., Clinical results of radionuclide therapy of neuroendocrine tumours with 90Y-DOTATATE and tandem 90Y/177Lu-DOTATATE: which is a better therapy option? Eur J Nucl Med Mol Imaging, 2011. 38(10): p. 1788-97.

132. Kong, G., et al., High-administered activity In-111 octreotide therapy with concomitant radiosensitizing 5FU chemotherapy for treatment of neuroendocrine tumors: preliminary experience. Cancer Biother Radiopharm, 2009. 24(5): p. 527-33.

133. van Essen, M., et al., Report on short-term side effects of treatments with 177Lu-octreotate in combination with capecitabine in seven patients with gastroenteropancreatic neuroendocrine tumours. Eur J Nucl Med Mol Imaging, 2008. 35(4): p. 743-8.

134. Claringbold, P.G., et al., Phase II study of radiopeptide 177Lu-octreotate and capecitabine therapy of progressive disseminated neuroendocrine tumours. Eur J Nucl Med Mol Imaging, 2011. 38(2): p. 302-11.

135. Eisenhauer, E.A., et al., New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1). Eur J Cancer, 2009. 45(2): p. 228-47.

136. Eriksson, B., et al., The role of PET in localization of neuroendocrine and adrenocortical tumors. Ann N Y Acad Sci, 2002. 970: p. 159-69.

137. Sundin, A., et al., PET in the diagnosis of neuroendocrine tumors. Ann N Y Acad Sci, 2004. 1014: p. 246-57.

138. van Essen, M., et al., Peptide receptor radionuclide therapy with 177Lu-octreotate in patients with foregut carcinoid tumours of bronchial, gastric and thymic origin. Eur J Nucl Med Mol Imaging, 2007. 34(8): p. 1219-27.

139. Carlsson, J., Effects of Low Dose-Rate Radiation on Cellular Survival, in Targeted Radionuclide Tumor Therapy, T. Stigbrand, Carlsson, J., Adams, G.P., Editor. 2008, Springer.

140. Welin, S., Midgut Carcinoid Tumours: New Diagnostic Procedures and Treatment, in Uppsala universitet, Medicinska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper. 2007, Uppsala: Uppsala. p. 53.

141. Oberg, K.E., et al., Role of somatostatins in gastroenteropancreatic neuroendocrine tumor development and therapy. Gastroenterology, 2010. 139(3): p. 742-53, 753 e1.

142. Fjallskog, M.L., et al., Treatment of malignant endocrine pancreatic tumors with a combination of alpha-interferon and somatostatin analogs. Med Oncol, 2002. 19(1): p. 35-42.

143. Eriksson, J., et al., Surgery and radiofrequency ablation for treatment of liver metastases from midgut and foregut carcinoids and endocrine pancreatic tumors. World J Surg, 2008. 32(5): p. 930-8.

144. Waldherr, C., et al., The clinical value of [90Y-DOTA]-D-Phe1-Tyr3-octreotide (90Y-DOTATOC) in the treatment of neuroendocrine tumours: a clinical phase II study. Ann Oncol, 2001. 12(7): p. 941-5.

145. Capello, A., et al., Tyr3-octreotide and Tyr3-octreotate radiolabeled with 177Lu or 90Y: peptide receptor radionuclide therapy results in vitro. Cancer Biother Radiopharm, 2003. 18(5): p. 761-8.

63

146. Teunissen, J.J., D.J. Kwekkeboom, and E.P. Krenning, Quality of life in patients with gastroenteropancreatic tumors treated with [177Lu-DOTA0,Tyr3]octreotate. J Clin Oncol, 2004. 22(13): p. 2724-9.

147. de Jong, M., et al., Tumor response after [(90)Y-DOTA(0),Tyr(3)]octreotide radionuclide therapy in a transplantable rat tumor model is dependent on tumor size. J Nucl Med, 2001. 42(12): p. 1841-6.

148. Cremonesi, M., et al., Dosimetry in Peptide radionuclide receptor therapy: a review. J Nucl Med, 2006. 47(9): p. 1467-75.

149. Barone, R., et al., Patient-specific dosimetry in predicting renal toxicity with (90)Y-DOTATOC: relevance of kidney volume and dose rate in finding a dose-effect relationship. J Nucl Med, 2005. 46 Suppl 1: p. 99S-106S.

150. Capello, A., et al., 111In-labelled somatostatin analogues in a rat tumour model: somatostatin receptor status and effects of peptide receptor radionuclide therapy. Eur J Nucl Med Mol Imaging, 2005. 32(11): p. 1288-95.

151. Melis, M., et al., Up-regulation of somatostatin receptor density on rat CA20948 tumors escaped from low dose [177Lu-DOTA0,Tyr3]octreotate therapy. Q J Nucl Med Mol Imaging, 2007. 51(4): p. 324-33.

152. Brans, B., F.M. Mottaghy, and A. Kessels, 90Y/177Lu-DOTATATE therapy: survival of the fittest? Eur J Nucl Med Mol Imaging, 2011. 38(10): p. 1785-7.

153. Moertel, C.G., et al., Treatment of neuroendocrine carcinomas with combined etoposide and cisplatin. Evidence of major therapeutic activity in the anaplastic variants of these neoplasms. Cancer, 1991. 68(2): p. 227-32.

154. Mitry, E., et al., Treatment of poorly differentiated neuroendocrine tumours with etoposide and cisplatin. Br J Cancer, 1999. 81(8): p. 1351-5.

155. Sorbye, H., et al., Predictive and prognostic factors for treatment and survival in 305 patients with advanced gastrointestinal neuroendocrine carcinoma (WHO G3): The NORDIC NEC study. Ann Oncol, 2012.

156. Ezziddin, S., et al., Impact of the Ki-67 proliferation index on response to peptide receptor radionuclide therapy. Eur J Nucl Med Mol Imaging, 2011. 38(3): p. 459-66.

157. De Vita, S., de Matteis, S., Laurenti, L., Chiusolo, P., Reddiconto, G., Fiorini, A., Leone, G., Sica, S., Secondary Ph+ acute lymphoblastic leukemia after temozolomide. Ann Hematol, 2005. 84: p. 760-762.

158. Travis, L.B., et al., Risk of leukemia after platinum-based chemotherapy for ovarian cancer. N Engl J Med, 1999. 340(5): p. 351-7.

159. Reimer, R.R., et al., Acute leukemia after alkylating-agent therapy of ovarian cancer. N Engl J Med, 1977. 297(4): p. 177-81.

160. Esser, J.P., et al., Comparison of [(177)Lu-DOTA(0),Tyr(3)]octreotate and [(177)Lu-DOTA(0),Tyr(3)]octreotide: which peptide is preferable for PRRT? Eur J Nucl Med Mol Imaging, 2006. 33(11): p. 1346-51.

161. Williams, L.E., G.L. DeNardo, and R.F. Meredith, Targeted radionuclide therapy. Med Phys, 2008. 35(7): p. 3062-8.

162. Cremonesi, M., et al., Dosimetry for treatment with radiolabelled somatostatin analogues. A review. Q J Nucl Med Mol Imaging, 2010. 54(1): p. 37-51.

163. Garkavij, M., et al., 177Lu-[DOTA0,Tyr3] octreotate therapy in patients with disseminated neuroendocrine tumors: Analysis of dosimetry with impact on future therapeutic strategy. Cancer, 2010. 116(4 Suppl): p. 1084-92.

164. Sward, C., et al., [(177)Lu-DOTA(0)-Tyr (3)]-Octreotate Treatment in Patients with Disseminated Gastroenteropancreatic Neuroendocrine Tumors: The Value of Measuring Absorbed Dose to the Kidney. World J Surg.

64

165. de Jong, M., et al., Tumour uptake of the radiolabelled somatostatin analogue [DOTA0, TYR3]octreotide is dependent on the peptide amount. Eur J Nucl Med, 1999. 26(7): p. 693-8.

166. Velikyan, I., et al., In vivo binding of [68Ga]-DOTATOC to somatostatin receptors in neuroendocrine tumours--impact of peptide mass. Nucl Med Biol. 37(3): p. 265-75.

Acta Universitatis UpsaliensisDigital Comprehensive Summaries of Uppsala Dissertationsfrom the Faculty of Medicine 831

Editor: The Dean of the Faculty of Medicine

A doctoral dissertation from the Faculty of Medicine, UppsalaUniversity, is usually a summary of a number of papers. A fewcopies of the complete dissertation are kept at major Swedishresearch libraries, while the summary alone is distributedinternationally through the series Digital ComprehensiveSummaries of Uppsala Dissertations from the Faculty ofMedicine.

Distribution: publications.uu.seurn:nbn:se:uu:diva-183417

ACTAUNIVERSITATIS

UPSALIENSISUPPSALA

2012