Revisiting BCG: The potential of rescue BCG therapy for BCG-unresponsive non-muscle-invasive bladder cancer

To evaluate the role of Rescue BCG in the treatment of BCG-unresponsive nonmuscle-invasive bladder cancer (NMIBC), in order to inform clinical decision-making especially when access to alternative therapies is limited.

From an institutional database, patients who met the criteria of BCG-unresponsive NMIBC between 2002 and 2023 were identified and sorted into 2 cohorts: those who received additional BCG therapy immediately after BCG-unresponsive designation and those who received alternative treatments such as intravesical chemotherapy and radical cystectomy. Primary endpoint was progression-free survival (PFS). Secondary endpoints included high-grade (HG) recurrence-free survival (RFS) and overall survival (OS).

A total of 120 patients with BCG-unresponsive NMIBC were evaluated. Of these, 66 received Rescue BCG, and 54 did not. Both cohorts were similar in demographics, although the Rescue BCG cohort had significantly more HG T1 disease. The 1-year PFS for Rescue BCG was 95.3% compared with 84.5% for No Rescue BCG (log rank, P = 0.4). Multivariable analyses showed Rescue BCG significantly reduced disease progression (HR: 0.38, 95% CI, 0.14-0.99) and improved overall survival (HR: 0.18, 95% CI, 0.04-0.79), though no difference in HG recurrence was found. Limitations include retrospective design.

Use of rescue BCG was associated with reduced risk of progression and improved overall survival when compared to No Rescue BCG. There was no significant difference in PFS between the No Rescue BCG cohort and in patients who had a HG recurrence within 2 years of being treated with Rescue BCG suggesting that a trial of Rescue BCG does not compromise overall oncologic outcomes.