Survival outcomes of small cell variant bladder cancer: Analysis from nationwide study.

4606 Background: Small cell carcinoma of bladder (SCB) is a rare and aggressive histological subtype. While the survival impact of various treatment modalities for the classic urothelial bladder cancer has been well-researched, limited studies exists on the survival outcomes of these treatment modalities in patients with SCB, primarily due to the exclusion of these patients from clinical trials. This study aims to explore the impact of different treatment modalities on the survival outcome of patients with SCB using data from a large nationwide registry. Methods: This retrospective study queried the National Cancer Database from 2004 to 2020 and followed STROBE guidelines. The primary analytic cohort included patients diagnosed with locoregional SCB based on the TNM stage (T1-T4, N0-N3, M0). Treatment modalities comprised perioperative systemic therapy combined with definitive surgery (PST), concurrent chemoradiation (CR), surgery only (S), Radiation therapy only (RT) and systemic therapy only (ST). This study utilized Kaplan-Meier survival analysis and the Cox Proportional regression. Results: The study included 4,658 patients with locoregional SCB. The analysis revealed 236 (4.82%) patients with SCB received PST, 752 (15.36%) got CR, 612 (12.50%) underwent S, 3,029 (61.85%) received ST, and 268 (5.47%) had RT. The median overall survival was 64.49 months (CI: 41.4-75.1, P < 0.001) with PST, 29.27 months (CI: 22.9-35.88), with CR, 14.13 months (CI: 9.92-21.65) with S alone, 21.29 months (CI: 18.53-23.69) with ST, and 7.82 months (CI: 6.24-9.53) with RT alone. In the multivariate analysis, combining perioperative systemic therapy with surgery led to a 54% reduction in hazards of death (HR: 0.46; CI: 0.37-0.58) compared to surgery alone, whereas CCR achieved a 41.16% (HR: 0.59; CI: 0.47-0.73) decrease in hazard, illustrating the effectiveness of multimodal treatment for SCB. Conclusions: Treatment approaches with either systemic therapy combined with definitive surgery or concurrent chemoradiation enhanced survival outcomes, highlighting the significance of a multimodal approach for patients with SCB. Table: see text