A retrospective study on tolerability and complications of bacillus Calmette-Guérin (BCG) instillations for non-muscle-invasive bladder cancer.

Objectives: The objective was to evaluate the tolerability of BCG treatment and to evaluate the effects of interruption on treatment outcomes. The incidence and characteristics of severe complications were observed. Methods: From hospital records, all bladder carcinoma patients treated with BCG instillations in the institution from 2009-2015 were retrospectively identified. The reasons for interruption, treatment outcome, number of instillations, and diagnosis of BCG infection were recorded. Results: Of the 418 patients who started BCG instillation therapy, 176 (42.1%) interrupted BCG treatment. Of those, 23 (5.5%) patients interrupted because of suspected BCG infection. Systemic BCG infection was found in seven (1.7%), and local infection in five (1.2%) patients. Interruption of treatment was due to other adverse effects in 71 patients (17.0%), BCG failure in 46 patients (11.0%), and other reasons in 36 patients (8.6%). Fifty percent of interruptions due to adverse effects occurred within the first 6 months. The probabilities of tumor recurrence (20.0% vs 10.7%, p = 0.014, OR = 2.077, CI95% = 1.149-3.753) and disease progression (5.4% vs 1.2%, p = 0.018, OR = 4.534, CI95% = 1.152-17.840) were higher among patients whose BCG treatment was interrupted. Conclusions: Severe complications were encountered in only <5% of patients. Adverse effects requiring treatment interruption were more likely to happen within the first year of treatment. Interrupting BCG treatment due to adverse effects increased the risk of disease progression and tumor recurrence.