Publication:

Comparative Analysis of Very Reduced vs Full Dose BCG Treatment for High-RiskNon-Muscle Invasive Bladder Cancer:A Contemporary Experience from Chile

BACKGROUND:Adjuvant bacillus Calmette-Gu ́erin (BCG) is recommended for high-risk (HR) non-muscle invasivebladder cancer (NMIBC), but BCG shortages have led to exploration of reduced-dose regimens and shortened maintenancedurations out of necessity, with limited data on treatment efficacy in Latin America.OBJECTIVE:Oncological outcomes of HR-NMIBC patients treated with reduced (RD,1/4th dose) vs full dose (FD) BCGinstillations ofDanish Strain1331 BCG.METHODS:We performed a retrospective study of HR-NMIBC patients treated with BCG between 2003 and 2022 at ourcenter in Santiago Chile. We stratified patients according to either RD (1/4th dose) or FD BCG. Univariate and multivariableCox regression models were used to predict recurrence. Kaplan-Meier method was used to calculate survival estimates.RESULTS:Of a total of 200 patients, 116 (58%) had RD and 84 (42%) FD BCG. Median follow-up was 57 months (IQR:29–100). Patients who received FD BCG had a lower risk of recurrence (HR: 0.41, 95% CI 0.22–0.74) and high-grade(HG)-recurrence (HR: 0.30, 95% CI 0.15–0.61;p= 0.001). More patients in the RD vs FD group progressed to MIBC (10/84vs 2/116;p= 0.18). Additionally, patients were less likely to stop BCG treatment in the RD group compared to the FD groupdue to toxicity (5% vs 11%,p= 0.14).CONCLUSIONS:A 1/4th dose ofDanish Strain1331 BCG treatment was associated with worse recurrence free rate andHG-recurrence rate in our cohort. Patients with RD had lower discontinuation treatment rates due to a reduced toxicity profile.These findings would suggest that RD BCG would compromise oncological outcomes in HR-NMIBC patients.