Long-term treatment outcomes of intermittent androgen deprivation therapy for relapsed prostate cancer after radical prostatectomy

Abstract

Purpose Intermittent androgen deprivation therapy is an effective treatment for metastatic prostate cancer. However, no study to date has evaluated the long-term outcomes of this treatment among patients with prostate cancer after radical prostatectomy. We retrospectively examined the treatment outcomes of patients with prostate-specific antigen recurrence who underwent radical prostatectomy at our department. Materials and methods Of the 690 patients who underwent radical prostatectomy for local prostate cancer between 1988 and 2011, 129 patients who received androgen deprivation therapy for prostate-specific antigen recurrence were included in this study. Patient characteristics, luteinizing hormone-releasing hormone agonist administration, and outcomes were compared between the intermittent androgen deprivation group (n = 66) and the continuous androgen deprivation therapy group (n = 63). The non-recurrence and overall survival rates were compared between groups. Results Thirty-six patients (27.9%) experienced recurrence after luteinizing hormone-releasing hormone agonist administration. The 5-year non-recurrence rate and 10-year overall survival rate were higher in the intermittent group (92.9%) than in the continuous group (92.9 vs 57.9%, P < 0.001; and 95.9% vs 84.3%, P = 0.047, respectively). Furthermore, 63 patients (48.8%) showed a PSA nadir of less than 0.01 ng/mL after initiation of luteinizing hormone-releasing hormone agonist; among these patients, the non-recurrence rate was significantly higher in the intermittent androgen deprivation group (P = 0.003). Conclusions Intermittent androgen deprivation therapy for prostate specific antigen recurrence after radical prostatectomy contributed to improvement of the non-recurrence rate and overall survival, and can be considered an effective therapy for better prognosis.