Adequate Bacillus Calmette-Guérin maintenance therapy improves recurrence-free survival in high-risk non-muscle-invasive bladder cancer: A conditional survival study.

OBJECTIVE

To evaluate the impact of Bacillus Calmette-Guérin (BCG) maintenance therapy intensity on outcomes in patients with high-risk non-muscle-invasive bladder cancer (NMIBC) and identify the critical period of maintenance efficacy.

PATIENTS AND

METHODS

This retrospective cohort study involved 150 patients with high-risk NMIBC who received BCG induction therapy between January 2010 and September 2022. The patients were classified by maintenance intensity within 1 year: adequate maintenance (AM; 5-9 of 9 planned instillations) or inadequate maintenance (IM; 0-4 instillations). The primary endpoint was conditional recurrence-free survival (CRFS), assessed at baseline (0 months) and at 6, 12, 18, and 24 months postinduction. CRFS was estimated, and multivariable Cox regression identified predictors of recurrence at each conditional time point.

RESULTS

Of 150 patients, 77 (51.3%) received AM and 73 (48.7%) received IM. AM patients showed significantly better RFS, with 5-year rates of 85.9% vs. 63.9% for IM. The 5-year CRFS rates for AM remained consistently higher than IM at all time points (0, 6, 12, 18, and 24 months). In the multivariable analysis, IM was the only significant predictor of poorer RFS at baseline, 6, and 12 months, with this association diminishing at 18 and 24 months.

CONCLUSION

Adequate BCG maintenance-defined as at least five instillations within the first year-significantly reduces early recurrence in high-risk NMIBC. The benefit of maintenance intensity is most pronounced during the first 12 months, underscoring the importance of adherence to an adequate BCG regimen to optimize outcomes.