Analysis of sex-based differences to Bacillus Calmette-Guérin for non-muscle invasive bladder cancer.

Objective: To evaluate whether differences exist between men and women in response to intravesical BCG treatments. The incidence of urothelial carcinoma of the bladder is lower in women but they tend to present with more aggressive and advanced disease. Some prior studies also suggest there are sex-based differences in response to treatment for non-muscle invasive bladder tumors.

Methods: In this retrospective study, we reviewed all consecutive patients who received BCG at the CHU de Québec - Laval University from 2009-2019. Men and women were treated with intravesical BCG therapy following pathologic confirmation of urothelial carcinoma. Outcomes evaluated include recurrence, progression, and treatment tolerability. Recurrence was defined as a pathology confirmed cancer whereas progression was the new development of high-grade (recurrence) pathology or an increase of stage. Tolerability was defined according to the proportion of prescribed BCG received. All clinical details were obtained through review of the medical records, collaborated by pharmacy records for BCG administration. Competing-risk analysis was used to compare outcomes.

Results: Among 613 patients who received BCG at our institution between 2009-2019, 472 (77.0%) were men and 141 (23.0%) were women. The recurrence rate was not different between sexes, with a 5-year recurrence risk of 52% (95% CI: 36.93-65.4) among women compared to 57.5% (CI 95%: 51.9-62.6) among men. The overall non-progression rate at 1,3 and 5 years was 97.3% (95% CI: 95.6%-98.3%), 93.6% (95% CI: 91.2%-95.4%), and 91.7% (95% CI: 88.4%-94.1%), respectively. The completion of ≥5 induction BCG instillations and maintenance BCG use was similar in both genders.

Conclusions: We report a contemporary NMIBC cohort treated with BCG and find no clear evidence for sex-based differences in response to BCG treatment in regard of progression, recurrence, and tolerability.