Background: We retrospectively compared the 5-year survival rates of T1b-T3N0M0 prostate cancer patients treated either by endocrine therapy plus radical prostatectomy or endocrine therapy alone.
Methods: Clinical T1b-T3N0M0 prostate cancer patients were enrolled at 104 institutions in Japan. They were assigned to study 1 (n = 176), if they were indicated to prostatectomy, if not indicated, they were assigned to study 2 (n = 151). The indication of prostatectomy was based on the clinical judgement of physicians and/or patients. Those assigned to study 1 underwent prostatectomy and adjuvant endocrine therapy with or without preoperative androgen deprivation. Those assigned to study 2 were treated with leuprorelin acetate with or without chlormadinone acetate. They were followed-up every 3 months until death or for 5 years and over.
Results: Those assigned to study 1 were younger (mean age 67.2 vs 75.7 years), less advanced in clinical stage, and had lower prostate specific antigen levels (mean 43.8 vs 103.6 ng/mL). Death for any reason was observed less frequently in study 1 (n = 29, 16%) than study 2 (n = 50, 33%), and the 5-year overall survival rate was higher in study 1 (87 vs. 68%). However, prostate cancer deaths were comparatively seldom (9% in study 1 and 7% in study 2), resulting in the identical 5-year cause specific survival rate in both study groups (91%). In both study groups the overall survival was almost equal to the natural survival of age-matched men.
Conclusions: Endocrine therapy offers a reasonable survival rate in T1b-T3 prostate cancer patients within a 5-year follow-up. Observation will be extended to determine 10-year outcomes.