The sensitivity of initial transurethral resection or biopsy of bladder tumor(s) for detecting bladder cancer variants on radical cystectomy

Purpose: We determined the ability of bladder biopsy and transurethral resection of the bladder to accurately predict bladder cancer variants on radical cystectomy since certain variants may affect prognosis and treatment. Materials and Methods: We retrospectively evaluated the records of 302 patients who underwent biopsy and/or transurethral resection of the bladder followed by radical cystectomy from 2008 to 2010. The frequency of variant morphology and the sensitivity of the precystectomy material was determined using pathological findings at radical cystectomy as the final result. Results: Bladder cancer variants were identified in 159 patients (53%) on initial biopsy/transurethral resection and/or final pathological evaluation at radical cystectomy. The most common variant was urothelial carcinoma with squamous differentiation in 72 of 159 patients (45%), followed by micropapillary urothelial carcinoma in 41 (26%). In 9 patients (6%) variant morphology was identified only on biopsy/transurethral resection bladder and not on final radical cystectomy pathological assessment. The remaining 150 patients (94%) showed variant morphology on radical cystectomy with (79 or 53%) or without (71 or 47%) variant morphology on the preceding biopsy/transurethral resection. The sensitivity of variant detection showed a broad range by variant subtype. Overall, initial biopsy/transurethral resection sensitivity was 39% for predicting variant morphology on radical cystectomy. Conclusions: Overall sensitivity for predicting bladder cancer variants from biopsy/transurethral resection of the bladder sampling is relatively low. This is likely due to sampling and tumor heterogeneity rather than to an inaccurate pathological diagnosis. Additional predictive markers of variant morphology may be useful to determine which tumors contain aggressive variants that may alter outcomes or therapy.