Importance of androgen-deprivation therapy during enzalutamide treatment in men with metastatic castration-resistant prostate cancer following chemotherapy: results from retrospective, multicenter data

Abstract

Enzalutamide can significantly prolong the survival of patients with metastatic castration-resistant prostate cancer (mCRPC). However, there is a paucity of evidence on continuing androgen-deprivation therapy (ADT) for mCRPC. Here, we analyzed the effect of concomitant ADT during enzalutamide treatment in men with mCRPC following chemotherapy. We retrospectively reviewed the medical records of 232 patients with mCRPC who received oral enzalutamide (160 mg per day) following chemotherapy at 9 tertiary centers in Korea between 2014 and 2016. The primary endpoint was overall survival, while secondary endpoints included time to prostate-specific antigen (PSA) progression and radiographic progression-free survival. The median age of the patients was 71 years (interquartile range, 64-75 years). The proportion of patients in a grade group ≥4 was 77.6%. The rate of concomitant ADT was 29.3%, and the all-cause mortality rate was 27.1% (n = 63). Median overall survival, time to PSA progression, and radiographic progression-free survival were 24.0, 8.0, and 10.0 months, respectively. Notably, concomitant ADT showed a significant association with longer overall survival (median duration not reached vs. 18.2 months; p = 0.008). After adjusting for confounding factors, concomitant ADT was still associated with longer overall survival (hazard ratio, 0.35; 95% confidence interval, 0.17-0.72). Concomitant ADT during enzalutamide treatment may improve the survival of patients with mCRPC following chemotherapy.