Neoadjuvant chemotherapy plus radical cystectomy (NAC-RC) versus trimodality therapy (TMT) in early-stage small cell bladder cancer: Comparison of outcomes.

Abstract

476 Background: Small cell bladder cancer is a rare and aggressive histological variant with a paucity of data to guide the optimal management strategy in non-metastatic disease. NAC-RC and TMT (maximal transurethral resection of bladder tumor + chemoradiation) have been variably employed based on institutional preferences, and we aim to compare outcomes between these two approaches. Methods: We queried the National Cancer Database for adult patients with small cell bladder cancer diagnosed during the years 2004 to 2018. Patients with small cell histology and early-stage clinically node-negative bladder cancer (cT1-4N0M0) were included and divided into two groups based on the treatment strategy employed – NAC-RC or TMT. Patients who did not receive any definitive local therapy and those who received chemotherapy or radiation in the adjuvant setting were excluded. Fisher’s exact and Mann Whiney U tests were used to compare frequency distributions. Cox Proportional Hazards regression was employed for multivariate analysis of factors associated with overall survival. Models were adjusted for age, sex, race, income, educational level, clinical T stage, insurance status, and the Charlson Comorbidity Index. Results: A total of 1262 patients were identified – 629 (49.8%) underwent NAC-RC while 633 (50.2%) received TMT. Patients in the NAC-RC group were younger (median 67 vs. 74 years, P <0.001) and more frequently Males (81% vs 76%, p = 0.02). Clinical T stage was comparable between the groups (P = 0.38). Patients with private insurance (P < 0.001) and higher income tiers (P = 0.04) were more likely to receive NAC-RC in lieu of TMT. Overall survival in the NAC-RC group was significantly longer than the TMT group (median of 41.3 vs. 25.4 months, log-rank P < 0.001). On multivariable analysis, only the type of treatment modality employed was independently predictive of overall survival (Hazard Ratio of 1.22 for TMT, with 95% CI 1.05-1.43, P = 0.01). Conclusions: In early-stage clinically node-negative small cell bladder cancer, NAC-RC was associated with significantly longer overall survival compared to TMT.