Tolerability and efficacy of induction Bacillus Calmette-Guérin for non-muscle invasive bladder cancer

Intravesical Bacillus Calmette-Guérin (BCG) is the standard treatment for intermediate-risk, high-grade, and high-risk non-muscle invasive bladder cancer (NMIBC). However, it is associated with adverse effects, potentially causing treatment interruptions or discontinuation.

This study analyzed the tolerability and efficacy of induction BCG, with associated patient- and disease-related factors.

A retrospective analysis was conducted on BCG-naive patients diagnosed with high-grade NMIBC, who received induction BCG at our institution between 2011 and 2021. Tolerability was defined as the completion of a 6-week induction course of BCG without treatment interruption or discontinuation. Multivariable logistic regression was performed to determine risk factors associated with the inability to tolerate treatment.

Induction BCG was given to 203 NMIBC patients, where 147 (72%) patients tolerated the treatment. Treatment interruptions occurred in 44 (22%) patients, while 12 (5.9%) patients discontinued the treatment. The median length of interruption was 1 week, primarily due to concerns about urinary tract infection (UTI) (n = 18, 41%) or gross hematuria (n = 5, 11%). No significant difference in 1-year recurrence rates was observed between those who tolerated BCG and those who did not (50% vs. 48%). Risk factors associated with the inability to tolerate induction BCG included male sex (odds ratio [OR] = 5.76, p < 0.01), hypertension (OR = 3.47, p = 0.02), and low pre-treatment hemoglobin levels (OR = 0.73, p = 0.03).

Inability to tolerate BCG occurred in 28% of patients, with 5.9% experiencing discontinuation. Interruptions were short, mostly concerning UTI, and rarely leading to discontinuation. Poor tolerability was associated with male sex, hypertension, and low pre-treatment hemoglobin levels, highlighting critical targets for reducing the risk of BCG interruption or discontinuation.