Associations Between Female Sex and Treatment Patterns and Outcomes for Muscle-invasive Bladder Cancer

Abstract

ObjectiveTo investigate the association of female sex with the selected treatment for patients with nonmetastatic muscle-invasive bladder cancer. Sex is a known independent predictor of death from bladder cancer. A potential explanation for this survival disparity is difference in treatment pattern and stage presentation among males and females. Materials and MethodsUsing the surveillance, epidemiology, and end results-medicare data set, we identified 6809 patients initially diagnosed with nonmetastatic muscle-invasive bladder cancer between 2004 and 2014. We fit multivariable logistic regression and Cox models to assess the relationship of sex with treatment modality and survival adjusting for differences in patient characteristics. ResultsOf the 6809 patients with nonmetastatic muscle invasive bladder cancer, 2528 (37%) received a radical cystectomy while 4281 (63%) received an alternative bladder sparing intervention. Women were significantly more likely to receive a cystectomy (odds ratios [OR] 1.39; 95% confidence intervals [CI] 1.20-1.61), present at an older age with less comorbidities compared to men (P <.001). Women were also found to have worse bladder cancer-specific survival (CSS) than men (hazard ratio [HR] 1.18; 95% CI 1.05-1.32), no difference in overall survival (OS) (female HR 0.93; 0.86-1.01) and lower mortality from other causes (HR 0.78; 95% CI 0.70-0.86). There were no differences in OS and CSS by sex in patients with stage pT4a. ConclusionFemale sex predicted more aggressive treatment with radical cystectomy yet worse cancer-specific survival than males. This sex disparity in CSS reduced the known OS advantage observed in women.