BCG shortage for intravesical instillation is associated with early tumoral recurrence in patients with high-risk non-muscle invasive bladder tumours.

INTRODUCTION: During 2019 there was a worldwide shortage of BCG strains for intravesical instillation, limiting the availability of full dose schemes for maintenance courses. The main objective was to analyze the impact on tumoral relapse secondary to BCG shortage in our center. Secondary outcomes included recurrence and progression-free survival rates and tumoral relapse specific characteristics. METHODS: Retrospective cohort study including 158 subjects (64 treated during 2019 and 94 during 2017) with high-risk non-muscle invasive bladder cancer and treated with a combination of Transurethral bladder resection (TURB) followed by adjuvant intravesical instillation with BCG in a tertiary hospital in Spain. Basal characteristics of both groups were analyzed. Times to event of interest (relapse; including recurrence and/or progression) were estimated with Kaplan-Meier survival analysis. Disease-free survival rates were analyzed using a multivariable Cox regression model of proportional hazards. RESULTS: Median follow-up in the 2019 sample was 24 months and 50 months in the 2017 group with a median number of instillations of 8 and 12 respectively. Median time to relapse of 285 days (145-448) during 2019 and 382 days (215-567) in 2017 were observed (logRank p = 0.025). Further multivariable analysis revealed a proportional hazard ratio (HR) for disease-free survival rate of 1.87 (95% CI: 1.04-3.37 p = 0.036). No statistically significant differences in tumoral relapse characteristics were observed. CONCLUSION: BCG shortage and subsequent reduced-dose schemes used for intravesical instillation due to limited availability, increase early tumoral relapse rates. These findings are consistent with available evidence, showing the need for full-dose BCG courses.