ROLE OF 18F-FDG-PET CT IN GYNAECOLOGICAL MALIGNANCIES
Dr Anju Sahdev Reader in Imaging and Consultant Uro-Gynae Radiologist
St Bartholomew’s Hospital, Bart’s Health
and
Queen Mary University of London
NECL Alliance Education meeting Feb 2020
BASIC PRINCIPLES: PET CT
Positron emission
tomography (PET)
Computerised
tomography (CT) +
Positron
emitters
18Flurorine 68Ga 11Carbon 15Oxygen
Unstable elements emitting positrons
which are neutralised by electrons.
This neutralization produces 2
annihilation photons of 511KeV.
These photons are detected and imaged
on bismuth, lutetium or gadolinium
detectors. +
Tracers
fluoro-2-
deoxy-D-
glucose
(FDG)
PSMA
DOTATE
Determines the imaging findings
E.g. FDG: glucose molecule taken up by glucose
utilizing cells
Ch: increased cell turnover
PSMA: prostate receptor specific,
DOTATE: somatostatin receptors
18F-FDG most commonly used due to its long half-life of 110
min which allows transportation from cyclotrons
Taken up by all tissue using glucose
Increased glucose use= increased tracer uptake
Cancers usually have increased glucose uptake = increased
tracer uptake
Infection and inflammation also has increased glucose and
therefore tracer uptake
THEREFORE NOT SPECIFIC
The uptake can be quantified and SUV (standardized uptake
value) is the most frequently used
OVARIAN CANCER
The role of FDG PET CT in ovarian cancer
includes:
lesion characterisation and diagnosis
staging
detection of recurrence
DIAGNOSIS AND CHARACTERISATION
Indeterminate lesions on TVUS: SUV >3
Sens 58%, spec 78% Reiber et al*
PPV 86% and NPV 76% **
False positives: dermoids and inflammatory masses
False negatives: borderline tumours
Combined with RMI>150
improves Sens 100% and Spec 92.5% ***
*Reiber et al. AJR Am J Roentgenol. 2001 Jul; 177(1):123-9
**Hubner et al. Gynecol Oncol. 1993 Nov; 51(2):197-204
*** Risum et al Gynecol Oncol. 2007 Apr; 105(1):145-9
Comparable
to
combination
of TVUS and
MRI
STAGING AND RECURRENCE
Study Setting Sens Spec
De Laco P et al
Eur J Radiol. 2011
staging 78% 68%
Hynninen J et al
Gynecol Oncol. 2013
Pre op
advanced dx
Overall 83%
FDG-PET/CT and CECT
poor for
subdiaphragmatic,
small bowel serosa
bowel mesentery and
right upper abdomen.
Zimny M et al
Gynecol Oncol. 2001
recurrence 83%
Rising to 94%
If CA125
83%
Bhosale P et al
Int J Gynecol Cancer.
2010
recurrence CECT 54%
PET CT 58% in normal CA125
not
unequivocally
superior to
CECT alone
In both staging and recurrence, unequivocally superior for:
nodal and distant metastases
supradiaphragmatic disease
results in stage migration
Limited change in management by the detection of additional
small volume abdominal or extra-abdominal disease
Small volume peritoneal and serosal disease
ADVANTAGES OF PET: RECURRENCE
ADVANTAGES OF PET
Borderline size
nodes
ADVANTAGES OF CT
Combined evaluation
of bowel
DIFFICULTIES ON PET
Cystic disease usually negative on PET
Borderline and low grade malignancy
DIFFICULTIES ON PET
DIFFICULTIES ON PET
Nodal metastases in low grade disease
CURRENT GUIDELINES: OVARIAN CANCER
RCR 2016 SIGN guidelines 2013 American NCCN 2017
• No role in primary
staging
• Rising CA125 with
negative or equivocal
cross-sectional imaging
Not routinely
recommended in the
diagnosis, staging,
surveillance or at
recurrence of epithelial
ovarian cancer
• Not routine for initial
adnexal masses, staging,
surveillance following
complete response
• Clinical relapse or Serially
rising CA-125 with or
without previous
chemotherapy
Evidence-based indications for the use of PET CT in the UK. Collaborative document 2016
American National Comprehensive Cancer Network
POTENTIAL ROLES
In patients with apparent solitary sites of
recurrence on CT prior to curative surgery
In patients with persistently raised CA125, high
RMI and normal TVUS?
Basu et al. PET and PET CT imaging of gynecological malignancies: present and
future. Expert Rev Anticancer Ther 2009;9:75-96
Prakash et al. Role of PET CT in ovarian cancer. AJR 2010 W464-470
CERVICAL CANCER
The role of FDG PET CT in cervical cancer includes:
Staging of locally advanced disease
• Extent of nodal and visceral metastases
• Microscopic metastases
• best performance with SCC, poor with adenoca
detection of recurrence
• Distinguishing between treatment effects and
recurrence locally
• Distant disease
Mapping the upper limit of
nodal metastases
Micro metastatic nodal metastases
PET CT PERFORMANCE
Stage dependent:
Early stage
Pooled data and meta analysis
PA node Sens 34% and Spec 97%
In early stage CaCx, mean size nodes 5mm*
Pelvic nodes Sens 53% (MRI 38%), Spec 90% (MRI 98%)
PA nodes Sens 25% and Spec 98%
*Wright et al Cancer. 2005 Dec 1; 104(11):2484-91
** Kang S et al J Nucl Med. 2010 Mar; 51(3):360-7
No added
benefit
over MRI
PET CT PERFORMANCE
Sens% Spec% PPV% NPV% Acc%
Sironi S Radiology 2006 (>1000 nodes)
72 99 81 99 99
Wright JD Cancer. 2005
25 98 50 93
Havrilesky LJ Gynecol Oncol. 2005
Pooled PA node data
79 96-99 Sensitivity of
detecting small
nodal metastases is
poor for all
modalities, 18F-FDG
PET CT offers the
best sensitivity in
advanced cervical
cancer.
Advanced stage
RECURRENT DISEASE
PET CT, by RCR and ANCCN guidelines, has been advocated in
the detection of clinically suspected recurrent disease when
cross-sectional imaging is equivocal
• early detection loco-regional treatment failure suitable for
salvage therapy
• to identify unsuspected asymptomatic distant metastatic
disease
Grigsby PW. Gynecol Oncol. 2007. (Suppl 1):S27-9.
Chung HH et al. Gynecol Oncol 2006
Distinguishes
between
residual or
recurrent
disease and post
tx changes
LOCAL RECURRENCE VS RT CHANGES
Pre Post
Small local recurrence
10 months post CRT
DISTANT DISEASE RECURRENCE
>90% are pelvic or para-aortic nodal recurrences
Findings
Kitajima et al Eur J Nucl Med Mol Imaging.
2010 Aug; 37(8):1490-8.
Sens 92% and Spec 93%
Chu Y et al Nucl Med Commun. 2014 Feb;
35(2):144-50.
Meta-analysis
Sens 94% and Spec 84%
Scarsbrook et al Eur J Nucl Med Mol Imaging.
2017 Apr; 44(4):581-588.
Sens 94% , NPV 95%
Spec 62%, PPV 59% *, Acc 74%
* PET CT 8-16 wks after CRT False –ve
<10mm PA
nodes
False +ve
mediastinal
nodes
EMERGING APPLICATIONS
Improve delineation of metabolic tumour volume (MTV) defined with PET CT/PET MRI
cervical primary and pelvic and PA nodes
False –ve 12% PA nodes
Herrera FG et al. Front Oncol. 2013
*Burger IA Gynecol oncol 2013
Assesses treatment response and predict survival outcome Persistent FDG uptake at the end of treatment with chemo radiotherapy
confers a poor 5-year survival outcome * 46%
No residual uptake 5-year survival 92%
Development of new uptake 5- year survival 0%
Higher pre-treatment SUV of the primary tumour and nodes predicts higher
likelihood of persistent FDG uptake at EOT ** and higher risk of nodal
metastases *Grigsby et al J Clin Oncol. 2004 Jun 1;
22(11):2167-71
**Kidd EA, Siegel BA, Dehdashti F, Grigsby PW
Cancer. 2007 Oct 15; 110(8):1738-44.
KEY POINTS IN CERVICAL CANCER
Improves detection of distant nodal disease in
ADVANCED disease
High sensitivity for distant recurrent disease detection
making is suitable for use in treatment planning
including exenterative surgery
SUV max values are biomarkers for response, survival
and predicting recurrence
ENDOMETRIAL CANCER
The role of FDG PET CT in endometrial cancer is limited:
physiological uptake of endometrium, limited use to detect EC
Poor spatial resolution for local myoinvasion compared to MRI
Need and importance of detecting microscopic nodal or distant
disease for patient management is controversial.
PET CT continues to provide only modest improvement in the
detection of microscopic nodal metastasis even in patients with
high-risk endometrial cancer
Useful adjunct to conventional imaging in detection of unexpected
nodal or distant disease in young patients being considered for
pelvic exenterative surgery for central recurrence of endometrial
cancer
Bollineni et al
J Nucl Med. 2016 Jun;
57(6):879-85
Meta-analysis
Sens 95% and Spec 91% in detection of
recurrence
Kadkhodayan et al
Gynecol Oncol. 2013 Feb;
128(2):397-404.
Meta-analysis
Sens 96% and Spec 93% in detection of
recurrence
* No mandatory histological
confirmation
CURRENT GUIDELINES: ENDOMETRIAL CANCER
RCR 2016 SIGN guidelines 2013 American NCCN 2017
• No role in primary
staging
• Patients being considered
for exenterative surgery
• Suspected recurrence
with equivocal cross-
sectional imaging
Does not recommend PET
CT at initial diagnosis or
staging of endometrial
cancer
PET CT at initial staging or
at suspected recurrence if
metastatic disease is
suspected in select patients
Evidence-based indications for the use of PET CT in the UK. Collaborative document 2016
American National Comprehensive Cancer Network 2017
THE FUTURE?
PET CT
Long half life emitters using
(89)Zr, (124)I, and (90)Y
Tumour specific tracers and
ligands
PET MRI
One stop shop for all
gynae/pelvic cancers
Staging: local + distant disease
Tx Planning
Biomaker functionality
recurrence and tx planning
• Decreased dose
• Improved spatial and tissue
resolution
• ?Improve CRT
Thank You
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