Sex-specific Differences in the Quality of Treatment of Muscle-invasive Bladder Cancer Do Not Explain the Overall Survival Discrepancy.

Background: While bladder cancer is less common among women, female sex is associated with worse oncological outcomes.

Objective: To evaluate sex-specific differences in initial presentation and treatment patterns of muscle-invasive bladder cancer.

Design, Setting, And Participants: A retrospective study using the National Cancer Database to identify individuals diagnosed with muscle-invasive bladder cancer (cT2-T4aN0M0) between 2004 and 2013.

Outcome Measurements And Statistical Analysis: Multivariable logistic regression and negative binomial regression with Bonferroni correction were used to investigate seven treatment measures: care at a high-volume facility, receipt of definitive therapy, delayed treatment, receipt of neoadjuvant or adjuvant chemotherapy, receipt of pelvic lymph node dissection, and number of lymph nodes removed. The secondary outcome was overall survival.

Results And Limitations: We identified 27525 patients, 27.4% of whom were females. Females were diagnosed significantly more often with nonurothelial carcinoma (15.1% vs 9.9%, p<0.001), with squamous carcinoma being the most prevalent variant (46.9%). After Bonferroni correction, there was no difference in six out of seven treatment quality measures. Females were significantly less likely to experience delayed treatment (odds ratio 0.89, 95% confidence interval [CI] 0.84-0.93, p<0.001). Females had significantly worse overall survival compared with males (hazard ratio 1.04, 95% CI 1.00-1.07, p=0.030). Limitations arise from the retrospective design of the study.

Conclusions: Despite little difference in treatment quality measures, female sex is associated with worse overall survival among individuals with muscle-invasive bladder cancer. Our findings suggest that differences in treatment patterns are unlikely to explain the differences in overall survival. Future initiatives should focus on root causes for gender-specific differences in pathological staging and features at diagnosis.

Patient Summary: In this study, we did not find differences in the treatment of bladder cancer between men and women that could readily explain why women diagnosed with this disease are more likely to die.