Impact of trimodal therapy on survival outcomes in non-urothelial muscle-invasive bladder cancer: A nationwide analysis.

e16614 Background: Bladder-sparing strategies (BSS) are increasingly utilized in managing muscle-invasive bladder cancer (MIBC), with trimodal therapy (TMT) comprising of maximum possible local resection along with Chemoradiation being the most established approach. While current guidelines recommend TMT for organ-confined urothelial carcinoma of the bladder. It is also applied to non-organ confined disease. Furthermore, most evidence from retrospective studies and clinical trials focuses on urothelial histology. We aim to investigate the impact of TMT on overall survival (OS) in patients with non-urothelial MIBC. Methods: We utilized the National Cancer Database to identify patients with MIBC (T2-4, N0-2, M0) having non urothelial histology. We utilized Kaplan Meier analysis and cox proportional hazard modelling to study the impact of various treatment modalities on OS in patients with non-urothelial MIBC. Results: We identified a total of 3,298 patients with MIBC with non-urothelial histology. Among these, 2,240 (67.9%) received surgery with or without systemic therapy, and 1,058 (32.1%) were treated with TMT. The median OS was 48.2 months (95% CI: 40.54–54.24) for those who underwent surgery with or without Systemic therapy and 21.75 months (95% CI: 19.84–23.72) for those treated with TMT. In the multivariate analysis, higher hazard ratios (HRs) were observed for patients with non-academic facility treatment (HR: 1.15, 95% CI: 1.04–1.30, p < 0.01), Charlson comorbidity score ≥1 (HR: 1.24, 95% CI: 1.11–1.38, p < 0.001), and TMT treatment (HR: 1.12, 95% CI: 1.08–1.16, p < 0.001). Conclusions: In this study, we found surgery with or without systemic therapy was associated with better survival compared to TMT in patients with non-urothelial MIBC. These findings warrant further investigation and emphasize the need for careful patient selection and consideration of risk factors when opting for bladder-preserving approaches in patients with non-urothelial MIBC. Cox proportional hazards regression model in patients with non-urothelial MIBC. Variable HR (95% CI) P-value Facility Type Academic Non-Academic Ref 1.16 (1.04–1.30) <0.01 Charlson Dayson Comorbidity score = 0 >= 1 Ref 1.24 (1.11–1.38) <0.001 Grade Well or moderately differentiated Poor or undifferentiated Ref 1.01 (0.90–1.13) 0.91 Treatment type Surgery +/- Systemic therapy TMT Ref 1.12 (1.08–1.16) <0.001