Impact of Androgen Deprivation Therapy on Racial/Ethnic Disparities in the Survival of Older Men Treated for Locoregional Prostate Cancer

Abstract

BACKGROUND: Racial disparities persist in prostate cancer (CaP) treatment and survival, but disparities in androgen deprivation therapy (ADT) and the degree to which it affects racial differences in survival remains to be fully assessed. METHODS: Using the Surveillance, Epidemiology and End Results-Medicare linked data, we examined a large cohort of men (N = 64,475) diagnosed with locoregional CaP during 1992 to 1999 and followed through 2003. The effects of ADT and race on survival were analyzed using a Cox proportional hazards model. RESULTS: The receipt of ADT was significantly lower in African Americans (24%) relative to Caucasians (27%), Asians (34%), and Hispanics (28.7%) (P < .05). Compared with Caucasian race, African American race was associated with a statistically significant increased mortality (HR = 1.26, 95% CI = 1.21-1.32), which remained significant after adjusting for ADT but was substantially decreased after controlling for primary therapies such as radical prostatectomy, radiation, and watchful waiting (HR = 1.06, 95% CI = 1.01-1.10) and was no longer statistically significant after controlling for comorbidities (HR = 0.98, 95% CI = 0.94-1.03). CONCLUSIONS: There were marked racial variations in the receipt of ADT, primary therapies (namely surgery and surgery combined with radiation), and comorbidities. However, racial disparities in survival were not affected by racial variations in ADT but were explained by racial variations in primary therapies and by racial differences in comorbidities.