Efficacy of androgen deprivation therapy (ADT) in patients with advanced prostate cancer: association between Gleason score, prostate-specific antigen level, and prior ADT exposure with duration of ADT effect

Abstract

Background: The purpose of this study was to compare predictive factors for the efficacy of androgen deprivation therapy (ADT) in men with hormone-sensitive prostate cancer (HSPC) either with (M+) or without (M-) metastases.

Methods: A cohort of prostate cancer patients was identified from a medical oncology practice treated with ADT for presumed nonlocalized prostate cancer, evaluated the efficacy of ADT using prostate-specific antigen (PSA) time to progression (TTP) and compared factors associated with TTP in M- and M+ patients.

Results: In this 553 patient cohort 51% were M- and 49% M+. The median TTP on ADT for the M- group was 33.2 months, versus 15.9 months in the M+ group (P<.0001). In multivariate analyses, lower biopsy Gleason score (GS), the absence of metastases, and lower serum PSA at ADT initiation all were associated with the efficacy of ADT. The association between GS and TTP was confined to M+ patients, whereas the association between PSA at ADT initiation and TTP was confined to M- patients. Use of ADT as part of local treatment was associated with a shortened TTP in both groups (hazard ratio [HR], 1.45, 95% confidence interval [CI], 1.10-1.91).

Conclusions: In this large, retrospective study of HSPC patients in a medical oncology practice treated with ADT for nonlocalized prostate cancer, we found factors predicting efficacy of this treatment differed based on whether metastases were present at ADT initiation. The use of ADT as a part of local therapy was associated with a significantly decreased TTP, regardless of metastatic disease status.