Racial Disparity in Androgen Deprivation Therapy Utilization for Men with High-Risk Prostate Cancer Treated with Intensity-Modulated Radiation Therapy in the Modern Era – A SEER-Medicare Linked Database Analysis

Abstract

Multiple randomized trials have confirmed a survival benefit to utilizing concurrent androgen deprivation therapy (ADT) with definitive radiotherapy for high-risk prostate (PCa). Further investigation into the optimal duration of ADT have suggested a disease-specific survival benefit to longer duration ADT. Previous studies suggest that longer durations of ADT are underutilized in general practice, but it remains unclear whether there are racial disparities in this under-utilization. We extracted PCa patients with Gleason 8-10 with N0M0 PCa from the SEER-Medicare linked database diagnosed from 2004 to 2012 who received intensity modulated radiotherapy (IMRT). ADT was defined as treatment with GnRH agonists (not orchiectomy or other forms of pharmacologic ADT) and the duration was calculated from all available and non-duplicate outpatient or carrier claims. The ADT duration was further categorized as 0, 1-23, and >24 months. Ultimately, 1472 White, 186 African American (AA) and 110 Asian patients were identified. Chi-squared tests was used to compare no ADT, short-term ADT (1-23 months) and long-term ADT (>=24 months) across all three races. AA patients who received IMRT were younger (median age of 72 years) as compared to White and Asian patients (75 years for both). There were no significant differences in the distribution of Gleason score or year of diagnosis. However, there were significant differences in ADT utilization, with 24.2% of AA patients receiving no ADT, compared to 13.8% and 16.4% of White and Asian patients, respectively. Specifically, 20% of White patients received long-term ADT compared to 14.5% and 13.4% for Asian and AA patients, respectively (p < 0.002). An analysis of Medicare claims confirms a widespread under-utilization of long-term ADT amongst high-risk PCa patients treated with definitive IMRT in the modern era. There is also racial disparity in ADT utilization, with AA patients less likely to receive any ADT and long-term ADT. Under-utilization in ADT may contribute to previously reported disparities in oncologic outcomes.