There is a differential in prostate cancer mortality between black and white men. Advances in precision medicine have shifted the research focus toward underlying genetic differences. However, non-biologic factors may play a large role in these observed disparities.

To measure the relative importance of race compared to healthcare and social factors on PCa specific mortality.

Using the Surveillance, Epidemiology, and End Results Database, we identified 514,878 PCa cases diagnosed at age ≥ 40 between 2004-2012. We also selected a subset of cases matching black men to white men by age, stage, and birth year. We stratified patients by age (40-54, 55-69, 70+) and disease stage resulting in 18 groups. Applying random forest methods with variable importance measures, we analyzed 15 variables and their interactions across four categories of factors (tumor characteristics, race, healthcare factors, and social factors) and their relative importance for PCa specific mortality.

Tumor characteristics at time of diagnosis were the most important factors for PCa mortality. Across all groups, race was less than 5% as important as tumor characteristics, and only more important than healthcare and social factors for 2/18 groups. Although race had a significant impact, healthcare and social factors, known to be associated with racial disparities, had greater or similarly important effects across all ages and stages.

Eradicating disparities in prostate cancer survival will take a multi-pronged approach including advances in precision medicine. Disparities will persist unless healthcare access and social equality is achieved among all populations.