Testosterone Reduction of ≥ 480 ng/dL Predicts Favorable Prognosis of Japanese Men With Advanced Prostate Cancer Treated With Androgen-Deprivation Therapy

Micro-Abstract Nadir testosterone < 20 ng/dL is the most significant prognostic factor for overall survival among Japanese patients treated with androgen-deprivation therapy (ADT). Both nadir testosterone (< 20 ng/dL; P =.026) and testosterone reduction (≥ 480 ng/dL; P =.030) are key prognostic factors for primary ADT in advanced prostate cancer in Japanese men. Introduction Reductions in testosterone concentration play a significant role in the treatment of prostate cancer. We studied the role of testosterone as a prognostic marker for advanced prostate cancer (stage C or higher) treated with primary androgen-deprivation therapy (ADT). Patients and Methods A total of 348 patients were treated using ADT as first-line therapy for prostate cancer at Chiba University Hospital between 1999 and 2016. Of these, 222 patients with advanced prostate cancer (stage C or higher) were enrolled onto this study. The prognostic values of serum testosterone level and other clinical factors were evaluated in association with prostate-specific antigen (PSA), progression-free survival during first-line therapy, and overall survival. Results Median age was 73 years. PSA at baseline was 86 ng/mL. Gleason scores of ≤ 6, 7, 8, and ≥ 9 were seen in 2.3%, 19.4%, 21.2%, and 41.9%, respectively. Mean follow-up was 60.5 months. Median testosterone at baseline was 482 ng/dL and nadir testosterone was 13 ng/dL. No variable associated with testosterone predicted progression-free survival. With regard to overall survival, multivariate analysis identified nadir testosterone ≤ 20 ng/dL (hazard ratio = 0.44, P =.026) and testosterone reduction ≥ 480 ng/dL (hazard ratio = 0.35, P =.030) as independent prognostic factors. With regard to progression-free survival, multivariate analysis identified nadir PSA ≤ 0.1 ng/mL (hazard ratio = 3.07, P <.001), presence of lymph node metastasis (hazard ratio = 1.67, P =.017), and time to nadir PSA (hazard ratio = 0.30, P <.001) as independent prognostic factors. Conclusion Our data suggested both nadir testosterone (< 20 ng/dL; P =.026) and testosterone reduction (≥ 480 ng/dL; P =.030) to be key prognostic factors for primary ADT in advanced prostate cancer in Japanese men.