Trimodal therapy effect on survival in urothelial vs non-urothelial bladder cancer

Objective: To address cancer-specific mortality free-survival (CSM-FS) differences in patients with urothelial carcinoma of the urinary bladder (UCUB) vs non-UCUB who underwent trimodal therapy (TMT), according to organ confined (OC: T2N0M0) vs non-organ confined (NOC: T3-4NanyM0 or TanyN1-3M0) clinical stages. Patients and methods: Within the Surveillance, Epidemiology, and End Results database (2004-2020), we identified patients with cT2-T4N0-N3M0 bladder cancer treated with TMT, defined as the combination of transurethral resection of bladder tumour, chemotherapy, and radiotherapy. Temporal trends described TMT use over time. Kaplan-Meier plots and multivariable Cox regression (MCR) models addressed CSM in UCUB vs non-UCUB according to OC vs NOC stages. Results: Of 5130 assessable TMT-treated patients, 425 (8%) harboured non-UCUB vs 4705 (92%) who had UCUB. The TMT rates increased for patients with OC UCUB from 92.4% to 96.8% (estimated annual percentage change of 0.4%, P < 0.001), but not in the NOC stages (P = 0.3). In the OC stage, the median CSM-FS was 36 months in patients with non-UCUB vs 60 months in those with UCUB, respectively (P = 0.01). Conversely, in the NOC stage, the median CSM-FS was 23 months both in UCUB and non-UCUB (P = 0.9). In the MCR models addressing OC stage, non-UCUB histology independently predicted higher CSM (hazard ratio 1.45, P = 0.004), but not in the NOC stage (P = 0.9). Conclusion: In OC UCUB, TMT rates have increased over time in a guideline-consistent fashion. Patients with OC non-UCUB treated with TMT showed a CSM disadvantage relative to OC UCUB. In the NOC stage, use of TMT resulted in dismal CSM, regardless of UCUB vs non-UCUB histology.