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.