Cancer‐Specific Survival of Trimodal Therapy Versus Radical Cystectomy in T2N0M0 Non‐Urothelial Bladder Cancer

INTRODUCTION: We hypothesized that, within organ-confined (OC, T2N0M0) non-urothelial carcinoma of urinary bladder (non-UCUB) patients, trimodal therapy (TMT) use does not differ from radical cystectomy (RC) regarding cancer control outcomes. METHODS: Within the SEER database (2004-2021), rates of TMT versus RC use in OC non-UCUB patients were calculated. Nearest-neighbor 1:1 propensity score matching (PSM) for age, sex, race/ethnicity, and histological subtype was applied. Cumulative incidence plots depicted 5-year cancer-specific (CSM) and other-cause mortality (OCM) rates. Multivariable competing risks regression (CRR) models were fitted. Sensitivity analyses were performed within squamous cell (SCC), neuroendocrine (NEC), and adenocarcinoma (ADK) and other histological subtypes. RESULTS: Of 814 OC non-UCUB patients, 310 (38%) received TMT versus 504 (62%) RC. After PSM, 5-year CSM rate was 50% after TMT versus 29% after RC and TMT was associated with 2.1-fold higher CSM relative to RC (multivariable HR [mHR]: 2.1, p < 0.001). In sensitivity analyses within 229 (28%) SCC, TMT patients had higher 5-year CSM rates relative to their RC-counterparts (67% vs. 22%, mHR: 4.3, p < 0.001). Similarly, within 314 (39%) NEC, TMT patients had higher 5-year CSM rates relative to their RC-counterparts (mHR: 1.8, p < 0.001). Conversely, within 118 (28%) ADK and 153 (19%) other subtypes, CSM after TMT did not differ from CSM after RC (33% vs. 15%, mHR: 1.4 and 43% vs. 33%, mHR: 1.4; p = 0.4). CONCLUSION: In OC non-UCUB patients TMT is associated with significantly higher CSM than RC. Most pronounced survival disadvantage was recorded within SCC and NEC patients.