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.
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. 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. 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. 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.