Young age and adequate BCG are key factors for optimal BCG treatment efficacy in non-muscle-invasive bladder cancer.

Objective: To investigate the impact of ageing on survival outcomes in Bacillus Calmette-Guérin (BCG) treated non-muscle invasive bladder cancer (NMIBC) patients and its synergy with adequate BCG treatment.

Method: Patients with NMIBC who received BCG treatment from 2001 to 2020 were divided into group 1 (< = 70 years) and group 2 (> 70 years). Overall Survival (OS), Cancer-Specific Survival (CSS), Recurrence-Free Survival (RFS), and Progression-Free Survival (PFS) were analyzed using the Kaplan-Meier method. Multivariable Cox regression analysis was used to adjust potential confounding factors and to estimate Hazard Ratio (HR) and 95% Confidence Interval (CI). Subgroup analysis was performed according to adequate versus inadequate BCG treatment.

Results: Overall, 2602 NMIBC patients were included: 1051 (40.4%) and 1551 (59.6%) in groups 1 and 2, respectively. At median follow-up of 11.0 years, group 1 (< = 70 years) was associated with better OS, CSS, and RFS, but not PFS as compared to group 2 (> 70 years). At subgroup analysis, patients in group 1 treated with adequate BCG showed better OS, CSS, RFS, and PFS as compared with inadequate BCG treatment in group 2, while patients in group 2 receiving adequate BCG treatment had 41% less progression than those treated with inadequate BCG from the same group.

Conclusions: Being younger (< = 70 years) was associated with better OS, CSS, and RFS, but not PFS. Older patients (> 70 years) who received adequate BCG treatment had similar PFS as those younger with adequate BCG treatment.