Maintenance Bacillus Calmette-Guerin for Ta T1 bladder tumors is not associated with increased toxicity: results from a European Organisation for Research and Treatment of Cancer Genito-Urinary Group Phase III Trial

OBJECTIVES: After transurethral resection, the local and systemic side effects of Bacillus Calmette-Guerin (BCG) instillations were assessed during a 6-week induction course followed by 3 weekly maintenance instillations at 3, 6, 12, 18, 24, 30 and 36 months to determine if BCG toxicity increases over time. METHODS: 487 patients who received BCG in a multicenter phase III trial were included. Side effects were divided into 5 different treatment periods: the first 6 weeks induction, months 3 and 6, month 12, the second year, and the third year. RESULTS: 99 (20.3%) patients stopped BCG due to side effects. 72 (14.8%) stopped due to local side effects, including 59 for BCG induced cystitis, 33 during the first 6 months. 46 (9.4%) stopped due to systemic side effects: 23 due to fever, 19 within 6 months, and 15 due to general malaise, 12 within 6 months. 68% who stopped due to side effects did so during the first 6 months. The percent stopping after 6 months due to local side effects does not increase and actually decreases for systemic side effects. CONCLUSIONS: The majority of local and systemic side effects are seen already during the induction and the first half-year of maintenance. During further maintenance BCG toxicity does not increase and instillations are generally well tolerated.