Baseline serum testosterone in men treated with androgen deprivation therapy and radiotherapy for localized prostate cancer

Abstract

Introduction: It is believed that men diagnosed with prostate cancer and a low baseline serum testosterone (BST) may have more aggressive disease, and it is frequently recommended they forego testosterone replacement therapy. We used two large Phase III trials involving androgen deprivation therapy and external beam radiation therapy to assess the significance of a BST.

Methods and materials: All patients with a BST and complete data (n = 2,478) were included in this analysis and divided into four categories: "Very Low BST" (VLBST) ≤16.5th percentile of BST (≤248 ng/dL; n = 408); "Low BST" (LBST) >16.5th percentile and ≤33rd percentile (>248 ng/dL but ≤314 ng/dL; n = 415); "Average BST" (ABST) >33rd percentile and ≤67th percentile (314-437 ng/dL; n = 845); and "High BST" (HBST) >67th percentile (>437 ng/dL; n = 810). Outcomes included overall survival, distant metastasis, biochemical failure, and cause-specific survival. All outcomes were adjusted for the following covariates: treatment arm, BST, age (<70 vs. ≥70), prostate-specific antigen (PSA; <10 vs. 10 ≤ PSA <20 vs. 20 ≤), Gleason score (2-6 vs. 7 vs. 8-10); T stage (T1-T2 vs. T3-T4), and Karnofsky Performance Status (60-90 vs. 100).

Results: On multivariable analysis age, Gleason score, and PSA were independently associated with an increased risk of biochemical failure, distant metastasis and a reduced cause-specific and overall survival (p < 0.05), but BST was not.

Conclusions: BST does not affect outcomes in men treated with external beam radiation therapy and androgen deprivation therapy for prostate cancer.