Abstract Objectives To investigate the real‐world clinical use of maintenance bacillus Calmette‐Guérin (mBCG) therapy for high‐risk non‐muscle‐invasive bladder cancer (HR‐NMIBC) in Japan. Patients and methods This multicentre, retrospective, observational study included patients who received intravesical mBCG for HR‐NMIBC following transurethral resection of bladder tumours between 2000 and 2023, and who were included in the Japan Urological Oncology Group registry database. Assessments included real‐world mBCG treatment duration, the completion rate of planned treatment, reasons for treatment discontinuation and mBCG effectiveness. Results The study included 886 patients (median interquartile range age 71.0 65.0–77.0 years; male, 83.5%). The median (interquartile range) treatment duration was 11 (6–17) months, with 43.8% of patients completing the physician‐determined planned treatment duration. The percentage of patients with mBCG treatment duration of 3, 6, 12, 18 and 24 months was 21.6%, 21.8%, 31.3%, 7.6% and 9.2%, respectively. Adverse events were the most common reason for mBCG discontinuation (49.1%). The recurrence‐free survival, progression‐free survival, overall survival and bladder preservation durations were numerically shorter in patients treated for 3 months. Conclusions This first comprehensive study of the real‐world use of mBCG treatment for HR‐NMIBC in Japan found diverse treatment patterns, with approximately 40% of patients receiving mBCG for <1 year, which is shorter than the guideline‐recommended treatment duration. The results underscore the need for early and sustained adverse event management, and provide valuable reference data for optimising mBCG therapy in clinical practice.
Miyake et al. (2025) studied this question.