Disparities in cause-specific mortality by race and sex among bladder cancer patients from the SEER database

Purpose: Previous literature shows that more bladder cancer patients overall die from causes other than the primary malignancy. Given known disparities in bladder cancer outcomes by race and sex, we aimed to characterize differences in cause-specific mortality for bladder cancer patients by these demographics.

Methods: We identified 215,252 bladder cancer patients diagnosed with bladder cancer from 2000 to 2017 in the SEER 18 database. We calculated cumulative incidence of death from seven causes (bladder cancer, COPD, diabetes, heart disease, external, other cancer, other) to assess differences in cause-specific mortality between race and sex subgroups. We used multivariable Cox proportional hazards regression and Fine-Gray competing risk models to compare risk of bladder cancer-specific mortality between race and sex subgroups overall and stratified by cancer stage.

Results: 17% of patients died from bladder cancer (n = 36,923), 30% died from other causes (n = 65,076), and 53% were alive (n = 113,253). Among those who died, the most common cause of death was bladder cancer, followed by other cancer and diseases of the heart. All race-sex subgroups were more likely than white men to die from bladder cancer. Compared to white men, white women (HR: 1.20, 95% CI: 1.17-1.23) and Black women (HR: 1.57, 95% CI: 1.49-1.66) had a higher risk of dying from bladder cancer, overall and stratified by stage.

Conclusion: Among bladder cancer patients, death from other causes especially other cancer and heart disease contributed a large proportion of mortality. We found differences in cause-specific mortality by race-sex subgroups, with Black women having a particularly high risk of dying from bladder cancer.