Long-term results of radical cystectomy and role of adjuvant chemotherapy for small cell carcinoma of the bladder

Objective: To review our experience with radical cystectomy for small cell carcinoma of the bladder, to compare outcomes with a cohort of patients with urothelial carcinoma, and to determine the effect of adjuvant chemotherapy and pathology re-review in this setting. Methods: Among 2427 patients who underwent radical cystectomy, 68 patients had small cell carcinoma of the bladder. Patients with small cell carcinoma of the bladder were compared with an unmatched cohort of 1146 patients with urothelial carcinoma, and were then matched (1:2) based on TNM stage. Survival was estimated using the Kaplan-Meier method, and Cox models were used to evaluate association of clinicopathological features with outcome. Results: Among the 68 small cell carcinoma of the bladder patients, 37 (54%) were found to have small cell carcinoma of the bladder only after pathology re-review. Patients with small cell carcinoma of the bladder had a higher rate of advanced (pT3/4) tumor stage (84% vs 46%; P<0.0001) and pN+ disease (37% vs 20%; P=0.001) compared with patients with urothelial carcinoma. When matched for stage and lymph node status, no significant difference in 5-year cancer-specific survival was observed between the two groups (27% vs 29%; P=0.64). Among small cell carcinoma of the bladder patients, those receiving adjuvant chemotherapy had improved 5-year overall survival compared with patients who did not receive adjuvant chemotherapy (43% vs 20%; P=0.03), and a trend toward superior cancer-specific survival (40% vs 23%; P=0.07). Conclusions: Small cell carcinoma of the bladder is often an unrecognized pathological entity, which is associated with a higher rate of locally advanced and N+ disease. However, although when matched for pathological features, survival outcomes appear similar to urothelial carcinoma. Small cell carcinoma of the bladder patients receiving adjuvant chemotherapy had improved overall survival and cancer-specific survival, and these results require further investigation.