SUO 2017: Inaccuracy of Clinical Staging After Neoadjuvant Chemotherapy for Muscle Invasive Bladder Cancer

Washington, DC (UroToday.com) Dr. Meyer and colleagues presented their work assessing inaccuracy of clinical staging after neoadjuvant chemotherapy for muscle invasive bladder cancer (MIBC). Based on randomized clinical trial data1, the standard of care for patients with MIBC is radical cystectomy (RC) + neoadjuvant chemotherapy (NAC). The authors report that they routinely perform restaging workup post-NAC prior to RC including imaging and cystoscopy with resection/biopsy. The objective of the current study was to evaluate the accuracy of restaging after NAC by comparing post-NAC with final RC pathology.

Dr. Meyer and colleagues reviewed 328 patients with MIBC at their institution between 2003 and 2016. Exclusion criteria for this study was evidence of lymph node or distant metastasis. Following NAC prior to RC, cystoscopy was performed and any visible tumor was resected and/or biopsy of scars obtained. Pathology accuracy was defined as concordance between biopsy/resection and final specimen with respect to presence or absence of disease. Further analysis was performed to compare differences between groups and identify predictors of accurate biopsy. Following NAC, 302 patients underwent cystoscopy, with 118 having biopsy/resection. There were 57 patients who had no evidence of disease on biopsy, and among these patients 26 (45.6%) had no evidence of disease on final pathology. Interestingly, among 17 patients who were cT2c after NAC, 13 (76%) were ≥pT3 on final RC pathology. Patients with accurate versus inaccurate biopsies differed with respect to race (p=0.02), tumor progression from non-MIBC (p=0.02), pathologic stage (p<0.01), and tumor size (p<0.01). On multivariate analysis, lack of tumor progression (p=0.03) and tumor size >2cm (p<0.01) were predictive of accurate biopsy. The sensitivity of post-NAC biopsy was 65.2% and specificity 89.7%. When imaging and gross cystoscopy findings were included, sensitivity of post-NAC clinical staging improved to 98.3%, while specificity decreased to 19.2%.
           
The authors concluded that there is inadequacy of clinical staging after NAC, particularly the ability of biopsy to accurately assess residual disease. Even when biopsies were obtained, 50% of cT0 patients were upstaged after RC, providing evidence that standard of care (RC after NAC) should be followed despite a seemingly encouraging response to NAC.

 Reference:
  1. Grossman HB, Natale RB, Tangen CM, et al. Neoadjuvant chemotherapy plus cystectomy compared with cystectomy alone for locally advanced bladder cancer. N Engl J Med 2003;349(9):859-866.
Presented by: Alexa Meyer, Johns Hopkins Hospital, Baltimore, MD
Co-Authors: Aaron Brant, Paige Nichols, Max Kates, Noah Hahn, Mark Schoenberg, and Trinity Bivalacqua

Written by: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre, Twitter: @zklaassen_md at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC
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