Adverse event-related discontinuation of maintenance Bacillus Calmette-Guérin therapy and oncological outcomes in non-muscle-invasive bladder cancer.

BACKGROUND

Maintenance Bacillus Calmette-Guérin (BCG) therapy is a key component of treatment for intermediate-risk to high-risk non-muscle-invasive bladder cancer (NMIBC) and an essential backbone for combination immunotherapy. However, its implementation remains limited by concerns regarding adverse events (AEs). We evaluated the association between AE-related discontinuation of maintenance BCG therapy and oncological outcomes.

METHODS

We retrospectively investigated 228 patients with NMIBC who had received adequate induction BCG and were subsequently scheduled to receive 1 year of maintenance BCG therapy between 2007 and 2020. Patients were categorized into an AE-related discontinuation group, a discontinuation for other reasons group, and a maintenance completion group. Recurrence-free survival (RFS) was assessed using Kaplan-Meier curves. Confounding and time-dependent bias were addressed by propensity score matching and landmark analyses at 3, 6, and 12 months.

RESULTS

Overall, 108 patients discontinued maintenance BCG because of AEs, 38 discontinued for other reasons, and 82 completed therapy (completion rate, 36%). Five-year RFS did not differ significantly between the AE-related discontinuation group and the maintenance completion group (89.4% vs. 83.5%, p = 0.314). No significant difference in RFS was observed after propensity score matching (p = 0.46). Landmark analyses consistently showed that AE-related discontinuation was not associated with an increased risk of recurrence.

CONCLUSIONS

Among patients who had received adequate induction BCG and predominantly achieved adequate BCG exposure, AE-related discontinuation of maintenance BCG was not significantly associated with worse oncological outcomes. Concerns regarding tolerability should not necessarily preclude initiation of maintenance BCG.