LAUSR

e16039 Background: There is an association between higher hospital and urologist case volume and improved survival outcomes for patients with bladder cancer. Limited data on facility volume and outcomes exists following trimodality bladder preservation with TURBT followed definitive chemoradiation (CRT). Methods: The National Cancer Database was queried for patients from 2004-2013 with urothelial bladder cancer (cT2-4aN0M0) receiving definitive CRT after TURBT. High-volume bladder preservation case volume (BPCV) was defined as facilities in the > 70th percentile of trimodality bladder preservation cases per ten years examined. We compared OS between high- and low-BPCV using Cox proportional hazard models. CRT was defined as > = 5040cGy pelvic RT with chemotherapy given within 21 days. Propensity matching was performed to match high- and low-volume centers. Results: A total of 666 treatment facilities treating 1,635 patients with bladder preservation were identified with a median follow-up of 26 months (range 2-136 months). A 70th percentile cutoff identified 497 patients that received treatment at 64 high-volume facilities. Median OS of patients treated at high BPCV centers was 37.0 months (95% CI, 27.9-33.6) versus 32.3 months (95% CI, 27.3-46.7) for patients treated at low BPCV centers (P = 0.004). High BPCV facilities were independently associated with a decreased hazard of death (HR, 0.86, 95% CI, 0.75-0.98; P = 0.031). When BPCV was analyzed as a continuous variable, an increasing number of bladder preservation cases per institute was also independently associated with improved OS (HR: 0.98, 95% CI, 0.97-0.99; P = 0.044). In the propensity score matched cohort, median OS of patients treated at high BPCV was 36.1 months (95% CI, 26.5-45.8) versus 28.1 months (95% CI, 23.9-32.3) for patients treated at a low BPCV facility (P = 0.016). Conclusions: In this observational cohort, treatment at a high BPCV facility was associated with improved OS. Causal factors for this finding may include greater institutional expertise in multidisciplinary bladder cancer care and potential advantages in treatment technology.