The impact of race on survival and treatment in Veterans treated for metastatic castration-resistant prostate cancer

Abstract: Background: Black individuals have higher incidence and mortality rates of prostate cancer than White individuals, and existing literature on treatment sequencing strategies in metastatic castration-resistant prostate cancer (mCRPC) is limited and conflicting. Understanding the interplay between race and treatment could optimize care and improve overall survival (OS). Methods: This retrospective observational cohort study assessed survival outcomes based on race and initial androgen receptor pathway inhibitor (ARPI) treatment among veterans with mCRPC. Participants included White or Black veterans diagnosed with mCRPC between January 1, 2011, and March 12, 2024, initially treated with either abiraterone or enzalutamide. The primary outcome was OS measured from the date of diagnosis and from the start of initial therapy. Kaplan-Meier estimates and Cox proportional hazards models were used to evaluate outcome differences by race and treatment. Results: A total of 12,355 patients met eligibility criteria. The mean age of the cohort was 74.57 years, with Black patients diagnosed approximately 4 years younger than White patients (71.77 vs 75.60, respectively; P<.001). Median prostate-specific antigen and mean Charlson comorbidity index scores were higher among Black patients. Median OS was higher in Black patients compared with White patients (36.3 months [95% CI, 35-38] vs 31 months [95% CI, 30.3-31.7], respectively; inverse probability of treatment weighting hazard ratio [IPTW HR], 0.80; P <.0001) Median OS was also longer among patients prescribed enzalutamide compared with those prescribed abiraterone (28 months [95% CI, 27.0-28.9] vs 23.7 months [95% CI, 23.1-24.2], respectively; IPTW HR, 1.14; P<.0001). No significant race-by-treatment interaction was observed. Conclusions: Black veterans with prostate cancer treated with ARPIs lived approximately 6 months longer after developing mCRPC but had a shorter lifespan-by about 3 years-compared with White patients. Differences in tumor biology may help explain why Black individuals develop prostate cancer at a younger age and exhibit better responses to cancer therapy.