Treatment patterns and prognosis in patients with Bacillus Calmette–Guérin-exposed high-risk non-muscle invasive bladder cancer: a real-world data analysis

Purpose: The International Bladder Cancer Group designated the subgroup that is resistant to Bacillus Calmette–Guérin (BCG) but does not meet the criteria for BCG-unresponsive NMIBC as “BCG-exposed high-risk NMIBC” to guide optimal trial design. We aimed to investigate the treatment patterns and prognoses of patients with BCG-exposed NMIBC. Methods: We conducted a retrospective chart review of 3283 patients who received intravesical BCG therapy for NMIBC at 14 participating institutions between January 2000 and December 2019. Patients meeting the criteria for BCG-exposed and BCG-unresponsive NMIBC, as defined by the Food and Drug Administration and International Bladder Cancer Group, were selected. To compare treatment patterns and outcomes, high-risk recurrence occurring more than 24 months after the last dose of BCG was defined as “BCG-treated NMIBC.” In addition, we compared prognoses between BCG rechallenge and early cystectomy in patients with BCG-exposed NMIBC. Results: Of 3283 patients, 108 (3.3%), 150 (4.6%), and 391 (11.9%) were classified as having BCG-exposed, unresponsive, and treated NMIBC, respectively. BCG-exposed NMIBC demonstrated intermediate survival curves for intravesical recurrence-free and progression-free survival, falling between those of BCG-unresponsive and treated NMIBC. Among patients with BCG-exposed NMIBC, 48 (44.4%) received BCG rechallenge, which was the most commonly performed treatment, and 19 (17.6%) underwent early cystectomy. No significant differences were observed between BCG rechallenge and early cystectomy in patients with BCG-exposed NMIBC. Conclusions: The newly proposed definition of BCG-exposed NMIBC may serve as a valuable disease subgroup for distinguishing significant gray areas, except in cases of BCG-unresponsive NMIBC.