MANAGEMENT OF RENAL TUMORS
By Dr Anil Gupta Moderator Dr Renu Madan
Classification of renal tumors
Renal parenchymal tumorsAdult renal tumors- Benign renal tumors- angiomyolipoma, oncocytoma, adenoma, cysts- Malignant renal tumors- Renal cell carcinoma(mc), sarcoma, lymphoma
Paediatric renal tumors- wilm's tumor, rhabdoid tumor
Renal Pelvis and Ureter- urothelial carcinoma
Renal Pelvis and Ureter
> 90% urothelial carcinoma
Accounts for 7% of all kidney tumors and 5% of all urothelial malignancies
Staging similar to bladder cancer
Treated in the line of bladder cancer
Renal parenchymal tumors
WHO classification of renal tumors(2016)
RENAL CELL CARCINOMA
Introduction
Malignant tumors of the kidney and renal pelvis account for nearly 4% of cancer cases and over 2% of cancer deaths in the United States
RCC represents over 90% of all malignancies of the kidney in adults
Male:Female ratio is 2:1
It predominantly in the sixth to eighth decade of life with median age at diagnosis around 64 years of age
Highly vascular
Not grossly infiltrative, except some collecting duct RCC and some sarcomatoid variants
No reliable histologic or ultrastructural criteria to differentiate benign from malignant renal cell epithelial tumors, except oncocytoma which is always benign
Epidemiology
Increases were seen mainly for localized cancers
- heightened clinical surveillance
- improved diagnostic capabilities
EstablishedTobacco exposure- Increases risk by about 50% in men and 20% in women
Obesity- Increases 24% for men and 34% for women for every 5 kg/m2 increase in BMI
Hypertension
Genetic factors- Von Hippel-Lindau (VHL) syndrome- heriditary papillary RCC- heriditary leiomyoma RCC- Birt-Hogg-Dube syndrome(BHD)- TS-ADPKD
Risk Factors
Putative (generally considered to be)Lead compoundsVarious chemicals (e.g., aromatic hydrocarbons)Trichloroethylene exposureOccupational exposure (metal, chemical, rubber, and printing industries)Asbestos or cadmium exposureCRF on dialysis and antihypertensiveRadiation therapyDietary (high fat/protein and low fruits/vegetables)
Genetic factors
Clinical Presentation
Called the great mimicker or the internists tumor
Many remain asymptomatic until the late disease stages
Classic triad - unilateral flank pain, hematuria, and palpable mass in 6-10%
Propensity to present with manifold clinical signs, symptoms, and paraneoplastic syndromes on the basis of local tumor extent, distant spread, biological activity
Can be true incidental tumors, classic triad symptoms, and constitutional symptoms (weight loss, fever, night sweats, anorexia, cough, malaise, etc.)
Anemia (21-41%)
Elevated sedimentation rate (50-60%)
Reversible hepatic dysfunction (10-15%)
Fever (7-17%)
Amyloidosis (3-5%)
Neuromyopathy (3%)
Hypercalcemia (3-6%)
Paraneoplastic syndromes
Erythrocytosis (3-4%)
Hypertension (22-38%)
Elevated human chorionic gonadotropin levels
Cushing syndrome
Hyperprolactinemia
Ectopic insulin and glucagon production
Raised alkaline phosphatase levels (10%)
Cachexia, weight loss (35%
Stauffer syndrome- liver dysfunction secondary to RCC- due to production of hepatotoxins or IL-6, IL-8
Grading
Fuhrman grading
A simplified, nuclear grading system, based only on size and shape of nucleoli, will replace present system (ISUP conference 2015)
Prognostic factors
Overall, tumor related factors such as pathologic stage, tumor size, nuclear grade, and histologic subtype= independent
Patient related factors such as CKD and co-morbidity have a significant impact on overall survival
Clinical findings s/o compromised prognosis in presumed localized RCC- Symptomatic presentation- Weight loss of more than 10% of body weight- Poor performance status
Other molecular prognostic factors,
Normogram
Karakiewicz PI et al
Diagnostic evaluation
Baseline workup - LFT, KFT, Creatinine clearance, CBC, ESR, coagulation study, urinalysis , Renal scintigraphy
Essential workupCT Scan
Complimentary workupUltrasound, MRI, PET, renal tumor biopsy
Emits sounds ( 3 to 7 Mhz) and receives echo
Strength of the echo determines the brightness setting for that cell
white for a strong echo, black for a weak echo, and varying shades of grey for everything in between
.
Ultrasonography
Normal KidneyMeasures 9-11 cm's
Has the same extent of echoes as liver
Cortex measures about 2.5 cm's
Central echoes are from fat surrounding renal pelvis.
Renal pelvis is filled with urine and is echo free. Note the posterior enhancement behind renal pelvis
Major criteria for a single simple cyst are:the mass is round and sharply demarcated with smooth walls
no echoes (anechoic) within mass
strong posterior wall echo indicating good sound transmission through the cyst
If US equivocal (complex cyst), or suggestive of malignancysolid or complex
with internal echoes
and irregular walls
if calcifications or septae are seen
if multiple cysts are clustered so that they may be masking underlying carcinoma
PROCEED TO CT....
CT Imaging
Radiologist's tumor
Most reliable method for detecting and staging renal cancers
Ideal CT examination for renal masses
- precontrast
- arterial phase (~25 seconds post injection)---> useful for identifying the renal arteries and for hypervascular masses
The nephrographic phase is generally the most useful for detecting renal lesions because the normal renal parenchyma is uniformly enhanced, yet there is still no excretion within the collecting system to interfere with the image. As a consequence, tumors generally appear low in density compared to the normal parenchyma. Highly vascular tumors, however, may be masked by the relatively high-density normal parenchyma. This phase also offers uniform enhancement of the veins making it the best time point for assessing renal vein and inferior vena cava thrombus arising from a tumor (Fig. 42.5). This phase has the highest sensitivity and specificity for renal masses (Fig. 42.6). Direct coronal and sagittal reconstructions have been particularly useful in identifying vessels, thrombi, and anatomic relationships between the renal cancer and adjacent structures.
- nephrographic (~90 seconds post injection)---> has the highest sensitivity and specificity for renal masses - excretory phase (~57 minutes post injection---> assessment of collecting system and renal pelvic involvement by a tumo
A change of 15 or more HUs demonstrates enhancement
CT provides information on- Function and morphology of the contralateral kidney
- Primary tumour extension; - Venous involvement; - Enlargement of locoregional LNs; - Condition of the adrenal glands and other solid organsA typical finding of RCC- heterogeneous pattern of enhancement-enhancement of iv contrast material by more than 15 HU should be considered an RCC until proved otherwise
MRI
MRI is used to evaluate solid tumors seen on CT if a patient is unable to receive IV contrast.
Vascular invasion, IVC thrombi are better demonstrated than CT
Using bight blood technique running blood shows bright signals except thrombus which shows as defects within the lumen
PET Scan
For patients with high risk of metastatic RCC
Good specificity but suboptimal senstivity
At present its best role is for patients with equivocal findings in conventional imaging
Radiolabelled monoclonal antibody to CA-IX is virtually present in all ccRCC
Monoclonal antibody G250 labelled PET is explored
Intravenous pyelographyPros- provide valuable information pertaining to the pyelocalyceal system- less resources required Cons- limited sensitivity for renal parenchymal pathologies and small renal masses- time consuming-Contrast toxicity
Renal angiogram- now limited role- guiding the operative
approach when attempting to perform a partial nephrectomy
Renal tumor biopsy
Can be performed under LA, with core needle or fine needle
At least two good quality cores should be obtained
Peripheral biopsies are preferable for larger tumours, to avoid areas of central necrosis
A coaxial technique allows multiple biopsies
Sensitivity- 99.1 %
Specificity 99.7%
Diagnosis of tumour histotype is good
Complications - bleeding, infection, arteriovenous fistula, needle track seeding, pneumothoraxMoreover........ - sampling error, -difficulty interpreting limited tissue - now we have improved diagnostic accuracy of imaging modalities
90% of solid renal masses thought to be suspicious for RCC on imaging prove to be RCC on final pathologic analysis
Present day indications- radiologically indeterminate renal masses- select patient kept on active surveillance with small renal mass- obtain histology before ablative treatments- select the most suitable form of medical and surgical treatment strategy in the setting of metastatic disease
STAGING
- Renal hilar
- Caval (paracaval, precaval, and retrocaval)
-Interaortocaval
- Aortic (paraaortic, preaortic, retroaortic)
Clinical Staging
Survival by stage
Management of Localized RCC(Stage I)
Radical nephrectomy
Earlier gold standard( Robson et al, 1969)PrototypeEn bloc removal of the kidney and its perirenal fat, enveloping Gerota's fascia with I/L adrenal, proximal one-half of the ureter, and lymph nodes dissection from crus till the area of transection of the renal vessels( or aortic bifurcation)
Much has changed now
Only 7% of patients with RCC tumors larger than 4 cm have micrometastatic adrenal involvement
Adrenalectomy only if - extensive renal involvement- locally advanced- upper pole tumor- SRM adjacent to adrenals
LN dissection still contoversial
Recent studies failed to show survival benefit
More accurate pathological stagingpresent day indications of LN dissection- high grade tumor- sarcomatoid component- histologic tumor necrosis- large size of tumor (>10cm)- pT3 or pT4
Changes in radical nephrectomy
Open
Laparoscopic- Decreased need for postoperative analgesic drugs(24 mg vs 40 mg morphine- Shorter hospital stay(1.5 day vs 5 day- Shorter recovery period (4 wk vs 8 wk)Laparoscopy have similar DFS at 5 years and 10 years.as open surgery
Limitations of Laparoscopic procedure -two-dimensional imaging-restricted range of motion of the instruments-poor ergonomic positioning of the surgeon
Advantage over laproscopic- improved visualization- more degree of movements
Limited evidence currently available for radical nephrectomy
Robot assisted Radical nephrectomy
Complications of Radical Nephrectomy
Intraoperative complication- injury to any GIT organs or to any major blood vessels, pleural injuries can result in pneumothorax.
Postop complications- secondary hemorrhage, atelectasis, ileus, superficial and deep wound infections,renal failure, and incisional hernia.
Other well-recognized systemic complications include MI, CHF, pulmonary embolism, CVA, pneumonia, and thrombophlebitis
Results in CKD
Nephron sparing surgery(NSS)
Partial nephrectomy (PN)
Standard of care
Surgical removal of a kidney tumor along with a thin rim of normal kidney
Preserves renal functioning
Indications of NSS
Imperative- solitary kidney- B/L RCC
Relative- opposite kidney dysfunctioning
Elective(ideal) - easily resectable, small ( 3cm- resection>2cm with symptomatic peritumoral edema- resection>2 asymptomatic- gamma knife sx
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