Does race predict the development of metastases in men who receive androgen-deprivation therapy for a biochemical recurrence after radical prostatectomy?

Background: In this study among men who underwent radical prostatectomy (RP), African American men (AAM) were 28% more likely to develop recurrent disease compared with Caucasian men (CM). However, among those who had nonmetastatic, castration-resistant prostate cancer (CRPC), race did not predict metastases or overall survival. Whether race predicts metastases among men who receive androgen-deprivation therapy (ADT) after a biochemical recurrence (BCR) (ie, before CRPC but after BCR) is untested. Methods: The authors identified 595 AAM and CM who received ADT for a BCR that developed after RP between 1988 and 2015 in the Shared Equal-Access Regional Cancer Hospital (SEARCH) database. Univariable and multivariable Cox models were used to test the association between race and the time from ADT to metastases. Secondary outcomes included the time to CRPC, all-cause mortality, and prostate cancer-specific mortality. Results: During a median follow-up of 66 months after ADT, 62 of 354 CM (18%) and 38 of 241 AAM (16%) developed metastases. AAM were younger at the time they received ADT (63 vs 67 years; P <.001), had received ADT in a more recent year (2008 vs 2006; P <.001), had higher prostate-specific antigen levels at RP (11.1 vs 9.2 ng/mL; P <.001), lower pathologic Gleason scores (P =.004), and less extracapsular extension (38% vs 48%; P =.022). On multivariable analysis, there was no association between race and metastases (hazard radio, 1.20; P =.45) or any of the other secondary outcomes (all P >.5). Conclusions: Among veterans who received ADT post-BCR after RP, race was not a predictor of metastases or other adverse outcomes. The current findings suggest that research efforts to understand racial differences in prostate cancer biology should focus on early stages of the disease (ie, closer to the time of diagnosis).