Contemporary Outcomes of Patients with Nonmuscle-Invasive Bladder Cancer Treated with bacillus Calmette-Guérin: Implications for Clinical Trial Design

Abstract

Purpose: Recurrent disease after bacillus Calmette-Guérin treatment presents a therapeutic challenge. To aid trial development, the U.S. Food and Drug Administration defined "adequate bacillus Calmette-Guérin" therapy and adopted the "bacillus Calmette-Guérin unresponsive" disease state. Available data for efficacy benchmark comparison are outdated, leading to concerns about appropriate control arms and sample size calculations. We describe a contemporary cohort of patients with nonmuscle-invasive bladder cancer treated with intravesical bacillus Calmette-Guérin, and provide benchmark outcomes data.

Materials and methods: We retrospectively reviewed patients receiving adequate bacillus Calmette-Guérin therapy at a tertiary cancer center between January 2004 and August 2018. Unadjusted univariable analysis was conducted using the Pearson chi-square test. Kaplan-Meier estimates for recurrence-free survival-high grade, progression-free survival-muscle-invasive bladder cancer and overall survival were used to create survival curves and compared using the log-rank test.

Results: Of the 542 patients who received adequate bacillus Calmette-Guérin, 518 (90%) had European Association Urology high risk disease, with carcinoma in situ present in 175 (32%). With a median followup of 47.8 months, freedom from high grade recurrence at 1, 3 and 5 years was 81%, 76% and 74%, respectively, and progression-free survival was 97%, 93% and 92%. Progression to muscle invasion at 5 years was exclusively seen in patients with high risk disease (progression-free survival 91%; log-rank test, p=0.024).

Conclusions: A contemporary cohort of patients with nonmuscle-invasive bladder cancer treated with adequate bacillus Calmette-Guérin demonstrated markedly better outcomes than seen in prior studies. These data could be used in the design of clinical trials, to guide power calculations, as well as serve as benchmarks for comparison to evaluate nonrandomized studies.

Keywords: BCG vaccine; immunotherapy; urinary bladder neoplasms.