Impact of Demographic and Socioeconomic Factors on Survival Associated With Androgen Receptor Pathway Inhibitor Use in Metastatic Prostate Cancer: An Analysis of the Surveillance, Epidemiology, and End Results (SEER)-Medicare Database

PurposeAndrogen receptor pathway inhibitors (ARPIs) are guideline-recommended standard therapy for metastatic prostate cancer.However, real-world utilization and survival differences across demographic and socioeconomic groups remain incompletely characterized.We assessed factors associated with overall survival (OS) among ARPI users and non-users in a population-based cohort. MethodsWe performed a retrospective cohort study using Surveillance, Epidemiology, and End Results (SEER)-Medicare data (2013)(2014)(2015)(2016)(2017) of Medicare beneficiaries aged 65 or greater with metastatic prostate cancer (excluding secondary malignancies or <6 months of follow-up).ARPI exposure (abiraterone/enzalutamide) was identified via Medicare Part D claims.Patients were stratified by ARPI receipt, and Kaplan-Meier estimates and multivariable Cox proportional hazards models evaluated predictors of OS. ResultsA total of 5,889 patients were included; 2,298 (39%) patients received an ARPI.ARPI users were predominantly White (77.1%),resided in urban areas (98.1%), and more frequently belonged to higher socioeconomic groups (73.0%).Kaplan-Meier analyses demonstrated significant differences in OS by age and race among ARPI users, whereas among non-users, OS differed according to age, race, geographic location, socioeconomic status, and marital status.In multivariable analyses, among ARPI users, age ≥ 73 years was associated with an increased hazard of death (adjusted hazard ratio (aHR) 1.54, 95% confidence interval (CI) 1.39-1.71),whereas Black race was associated with a lower hazard of death than White race (aHR 0.83, 95% CI 0.71-0.97).Among non-users, age ≥ 73 years (aHR 2.25, 95% CI 2.01-2.51),low socioeconomic status (aHR 1.25, 95% CI 1.07-1.46),and never having married (aHR 1.53, 95% CI 1.33-1.77)were associated with worse OS. ConclusionIn this SEER-Medicare cohort, 39% of patients with metastatic prostate cancer received an ARPI.Older age was associated with worse OS regardless of ARPI use, whereas socioeconomic disparities in survival were observed only among patients who did not receive ARPI therapy.This observed association suggests that improving access to ARPIs may be associated with reduced outcome disparities in metastatic prostate cancer, though prospective studies are needed to determine causality.