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SIU 2019 39th Annual Society of International Urology Congress

SIU 2019: PET Imaging in Renal Cell Carcinoma and Urothelial Cancers

Athens, Greece (UroToday.com) Dr. Eoin MacCraith continued the PET imaging session with a nice overview of the use of PET-FDG in renal cell carcinoma (RCC) and urothelial cancers. PET is beneficial in diagnostics, staging, prognostics, and assessing therapeutic response, but it is currently not recommended for routine use.

One of the earlier tracers used is the 18F-FDG which is highly expressed in aggressive tumors with its uptake regulated by glucose-1-transporter expression. Aggressive tumors are highly avid for glucose.

The role of PET FDG imaging for the diagnosis of RCC is limited as the tracers are excreted through the urinary system there is a high false negative, as the tracer can obscure the tumor.

The sensitivity of conventional CT vs. PET for detection of RCC is 91.7% vs. 60%.1 However, when comparing the accuracy of PET vs. CT for detecting distant metastases of RCC, PET is shown to be more accurate (94% vs. 89%).2 The sensitivity/accuracy for the detection of bone metastases when comparing bone scans to PET is 77.5%/59.6% vs. 100%/100%.3 The pooled sensitivity of PET for the detection of RCC is 50-60%.4 Higher FDG uptake correlates with higher stage and grade5 (Figure 1).

Promising results are reported when assessing the role of PET FDG in RCC recurrence. The sensitivity of PET FDG in this scenario is reported at 90%, specificity 91%, and an accuracy of 90%.6 Moreover, PET FDG was shown to alter management in 43% of metastatic/recurrent RCC lesions.7

Despite these favorable results, the routine use of PET-FDG is not recommended in RCC, but it may be beneficial when there is diagnostic uncertainty on conventional surveillance CT.

The metabolic quantitation in PET can be performed by measuring the maximum standardized uptake value (SUVmax). SUVmax on PET correlates with a poorer prognosis.8 In metastatic RCC treated with sunitinib, the SUVmax for PET at 16 weeks correlated with decreased survival.9 A partial metabolic response was associated with improved overall survival/progression-free survival. An important finding was that the highest survival rates were seen in patients with the greatest post-therapeutic reduction in SUVmax.10 This important finding may potentially mean that a change in FDG uptake may be a useful indicator of Tyrosine Kinase Inhibitor's response.

In the next part of this talk, Dr. MacCraith moved on to discuss the role of PET FDG imaging in urothelial cancer. It is quite similar to RCC, demonstrating a limited role, due to the fact that this tracer is excreted through the urine which can obscure present tumors (Figure 2). However, there are data showing that PET FDG has better sensitivity than conventional CT for detecting pelvic node metastases (57% vs. 33%).11 The pooled sensitivity of PET CT for staging/restaging in urothelial cancer is 89%.12 PET FDG detected more disease than CT in 40% of cases and altered management in 68% of cases.13 Positive PET is associated with higher disease progression and reduced overall survival. Despite these advantages, they have not resulted in issuing a recommendation to routinely use this imaging modality.

For upper tract urothelial carcinoma (UTUC), PET FDG has been shown to be superior to conventional CT for detecting distant metastases and significantly altering management.14 It has better overall survival and progression-free survival for patients who show a response on PET after 2 cycles of chemotherapy, but again, this has not been enough to recommend routine use.

The EAU guidelines to date state that there are insufficient data on the use of FDG-PET/CT in muscle-invasive bladder cancer to allow a recommendation to be made. For RCC the recommendations are quite the same, with the guidelines clearly stating to not routinely use bone scan and/or PET CT for RCC staging.

Final take-home messages of this talk included that these advanced imaging modalities are not to be routinely used in diagnosis or staging of RCC and urothelial cancer. These imaging modalities could be a useful adjunct in surveillance when conventional imaging is inconclusive and may potentially alter management. Lastly, there is some use of PET CT in assessing therapeutic responses to tyrosine kinase inhibitors in metastatic RCC.


Figure 1- PET CT in renal cell carcinoma - Fused coronal PET/CT (A) and fused sagittal PET/CT (B) show increased FDG uptake in the primary RCC tumor in the right kidney (solid arrow), in a right adrenal gland metastasis (semidotted arrow), mediastinal lymph node metastases (dotted arrow), and bone metastases (interrupted arrow). Furthermore, there was markedly increased linear FDG uptake in a massive tumor thrombus in a dilated inferior vena cava (asterisk).15

SIU19_PET_CT.png

Figure 2- Urinary FDG excretion masking a bladder tumor. Axial fused FDG PET/CT image at standard windowing to an SUV max of 10 shows no obvious abnormality within the pelvis16

SIU19_FDG_PET.png



Presented by: Eoin MacCraith, Urology SpR, Department of Urology, Beaumont Hospital, Dublin, Ireland

Written by: Hanan Goldberg, MD, Urology Department, SUNY Upstate Medical University, Syracuse, New-York, USA @GoldbergHanan at the 39th Congress of the Société Internationale d'Urologie, SIU 2019, #SIUWorld #SIU2019, October 17-20, 2019, Athens, Greece

References:

  1. Kang DE, White RL, Jr., Zuger JH, Sasser HC, Teigland CM. Clinical use of fluorodeoxyglucose F 18 positron emission tomography for detection of renal cell carcinoma. The Journal of urology 2004; 171(5): 1806-9.
  2. Aide N, Cappele O, Bottet P, et al. Efficiency of [(18)F]FDG PET in characterising renal cancer and detecting distant metastases: a comparison with CT. European journal of nuclear medicine and molecular imaging 2003; 30(9): 1236-45.
  3. Wu HC, Yen RF, Shen YY, Kao CH, Lin CC, Lee CC. Comparing whole body 18F-2-deoxyglucose positron emission tomography and technetium-99m methylene diphosphate bone scan to detect bone metastases in patients with renal cell carcinomas - a preliminary report. Journal of cancer research and clinical oncology 2002; 128(9): 503-6.
  4. Wang HY, Ding HJ, Chen JH, et al. Meta-analysis of the diagnostic performance of [18F]FDG-PET and PET/CT in renal cell carcinoma. Cancer imaging : the official publication of the International Cancer Imaging Society 2012; 12: 464-74.
  5. Nakajima R, Nozaki S, Kondo T, Nagashima Y, Abe K, Sakai S. Evaluation of renal cell carcinoma histological subtype and fuhrman grade using (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography. European radiology 2017; 27(11): 4866-73.
  6. Kumar R, Shandal V, Shamim SA, Jeph S, Singh H, Malhotra A. Role of FDG PET-CT in recurrent renal cell carcinoma. Nuclear medicine communications 2010; 31(10): 844-50.
  7. Alongi P, Picchio M, Zattoni F, et al. Recurrent renal cell carcinoma: clinical and prognostic value of FDG PET/CT. European journal of nuclear medicine and molecular imaging 2016; 43(3): 464-73.
  8. Namura K, Minamimoto R, Yao M, et al. Impact of maximum Standardized Uptake Value (SUVmax) evaluated by 18-Fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG-PET/CT) on survival for patients with advanced renal cell carcinoma: a preliminary report. BMC Cancer 2010; 10(1): 667.
  9. Kayani I, Avril N, Bomanji J, et al. Sequential FDG-PET/CT as a biomarker of response to Sunitinib in metastatic clear cell renal cancer. Clinical cancer research : an official journal of the American Association for Cancer Research 2011; 17(18): 6021-8.
  10. Caldarella C, Muoio B, Isgro MA, Porfiri E, Treglia G, Giovanella L. The role of fluorine-18-fluorodeoxyglucose positron emission tomography in evaluating the response to tyrosine-kinase inhibitors in patients with metastatic primary renal cell carcinoma. Radiology and oncology 2014; 48(3): 219-27.
  11. Lodde M, Lacombe L, Friede J, Morin F, Saourine A, Fradet Y. Evaluation of fluorodeoxyglucose positron-emission tomography with computed tomography for staging of urothelial carcinoma. BJU international 2010; 106(5): 658-63.
  12. Lu YY, Chen JH, Liang JA, et al. Clinical value of FDG PET or PET/CT in urinary bladder cancer: a systemic review and meta-analysis. European journal of radiology 2012; 81(9): 2411-6.
  13. Apolo AB, Riches J, Schöder H, et al. Clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in bladder cancer. Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2010; 28(25): 3973-8.
  14. Tanaka H, Yoshida S, Komai Y, et al. Clinical Value of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Upper Tract Urothelial Carcinoma: Impact on Detection of Metastases and Patient Management. Urologia internationalis 2016; 96(1): 65-72.
  15. Ravina M, Hess S, Chauhan MS, Jacob MJ, Alavi A. Tumor thrombus: ancillary findings on FDG PET/CT in an oncologic population. Clinical nuclear medicine 2014; 39(9): 767-71.
  16. Lakhani A, Khan SR, Bharwani N, et al. FDG PET/CT Pitfalls in Gynecologic and Genitourinary Oncologic Imaging. Radiographics : a review publication of the Radiological Society of North America, Inc 2017; 37(2): 577-94.