Racial Differences in Secondary Treatment Pathways and Survival in Localized Prostate Cancer.

Importance: Black men are more than 2 times more likely to die of prostate cancer than White men. Identifying mechanisms underlying racial disparities is a critical prerequisite to health equity. Objective: To assess differences in treatment trajectories after primary treatment and their associations with mortality outcomes comparing Black and White patients with localized prostate cancer. Design, Setting, and Participants: This retrospective, population-based cohort study used SEER-Medicare data from non-Hispanic Black and White men 66 years or older enrolled in Medicare and diagnosed with localized prostate cancer between January 1, 2004, and December 31, 2017. Analyses were conducted between January 2025 and January 2026. Exposure: Race. Main Outcomes and Measures: Hazard ratios (HRs) assessed differences by race in secondary treatment receipt (ie, any treatment received >1 year after primary treatment) and mortality. Secondary analyses examined differences in the type of secondary treatment received (ie, secondary radiation therapy, novel systemic therapies, and/or androgen deprivation therapy). Results: Participants were divided into 2 cohorts based on primary treatment type: surgery (22 271 participants; 1312 [5.9%] Black and 20 959 [94.1%] White; mean [SD] age, 70 [4] years) and radiation therapy (60 885 participants; 6052 [9.9%] Black and 54 833 [90.1%] White; mean [SD] age, 73 [5] years) to enhance comparability within cohorts. Among participants who received primary surgery, 4275 (19.2%) received secondary treatment with no significant differences by race. Among participants who received primary radiation therapy, 17 058 (28.0%) received secondary treatment with no significant differences by race. In both cohorts, no differences were found in mortality outcomes among those who received secondary treatment. However, significant differences were found for those who did not receive secondary treatment, with Black patients at higher risk for both prostate cancer-specific and all-cause mortality. Secondary analyses suggest that the type of secondary treatment received differed by race. Conclusions and Relevance: In this cohort study of men treated for localized prostate cancer, treatment receipt after primary definitive treatment was similar by race. No mortality differences were found among those who received secondary treatment; however, observed mortality disparities among those who did not receive secondary treatment raise concerns about potential health care inequities.