Real-World Clinical Outcomes Among Patients With High-Risk Non-Muscle-Invasive Bladder Cancer Treated With Bacillus Calmette-Guérin: A SEER-Medicare Analysis.

INTRODUCTION: Contemporary data on clinical outcomes following Bacillus Calmette-Guérin (BCG) treatment in high-risk non-muscle-invasive bladder cancer (HR-NMIBC) are needed. This study evaluated recurrence and survival in US patients with HR-NMIBC who received BCG. METHODS: Using Surveillance, Epidemiology and End Results-Medicare data, we identified patients aged ≥ 65 years with a primary diagnosis of HR-NMIBC who received BCG (initiation date = index date). Post-BCG recurrence was assessed overall and by local NMIBC recurrence, progression to muscle-invasive bladder cancer (MIBC), and distant metastasis (DM). Event-free and overall survival were estimated using Kaplan-Meier analysis. Cystectomy use following recurrence was also evaluated. RESULTS: A total of 5490 patients with HR-NMIBC who received BCG were included, of whom 33.6% had high-grade Ta, 55.0% T1 (± Ta), and 11.4% Tis (± Ta/T1) at initial diagnosis. Over a median follow-up of 2.9 years, 2178 (39.7%) patients experienced recurrence, 97.2% occurring within the first 5 years after BCG initiation. Recurrence rates for local NMIBC recurrence, progression to MIBC, and DM increased from 15.9%, 4.1%, and 3.7% at 1 year to 33.6%, 15.9%, and 16.7% at 10 years, respectively. Recurrence was similarly high among patients with Tis (42.1%) and T1 (40.6%) disease. Among patients with recurrence, 312 (14.3%) underwent cystectomy, 83.3% of which within 1 year after recurrence. CONCLUSIONS: In this population-based study, patients with HR-NMIBC experienced substantial recurrence burden following BCG treatment, with the majority of recurrences occurring within 5 years after BCG initiation. These findings underscore the need for improved strategies to effectively delay or prevent recurrence in HR-NMIBC.