Insurance Disparity in Novel Hormonal Therapy Initiation in Patients With Metastatic Hormone-Sensitive Prostate Cancer: Medicare Advantage Versus Traditional Medicare

PURPOSE To examine whether Medicare Advantage (MA) enrollment is associated with differences in the timeliness of novel hormonal therapy (NHT) initiation, including abiraterone, enzalutamide, apalutamide, and darolutamide, for metastatic hormone-sensitive prostate cancer (mHSPC), compared with Traditional Medicare (TM), and to explore disparities by race, socioeconomic status (SES), and care setting. METHODS We conducted a retrospective cohort study using the Flatiron Health Research Database, including 3,215 patients age ≥65 years diagnosed with mHSPC between 2018 and 2023. Timely NHT initiation was defined as receipt within 45 days of diagnosis. Multivariable logistic regression models were adjusted for age, race/ethnicity, year of diagnosis, de novo metastatic status, Eastern Cooperative Oncology Group performance status, SES, and practice type, using inverse probability of treatment weighting to balance baseline characteristics between MA and TM groups. RESULTS Among the 3,215 patients, 2,011 (63%) were enrolled in TM and 1,204 (37%) in MA. Overall, 25% initiated NHT within 45 days of diagnosis. Compared with TM beneficiaries, MA enrollees was associated with lower odds of timely NHT initiation (adjusted odds ratio aOR, 0.82 95% CI, 0.70 to 0.95; P = .01). Differences were more pronounced among racial and ethnic minority patients (aOR, 0.54 95% CI, 0.37 to 0.77), individuals from lower-SES areas (aOR, 0.75 95% CI, 0.58 to 0.98), and patients receiving care in community settings (aOR, 0.80 95% CI, 0.67 to 0.95). CONCLUSION MA enrollment was associated with lower odds of timely NHT initiation compared with TM. These associations were particularly evident among underserved groups, highlighting the need to evaluate how MA program structures may influence equitable access to evidence-based cancer care.