The effect of continuous androgen deprivation treatment on prostate cancer patients as compared with intermittent androgen deprivation treatment

PURPOSE: To investigate the efficacy of androgen deprivation treatment (ADT) between continuous and intermittent ADT. MATERIALS AND METHODS: Between January 2006 and May 2015, 603 patients were selected and divided into continuous ADT (CADT) (n=175) and intermittent ADT (IADT) (n=428) groups. The median follow-up in this study was 48.19 (1.0-114.0) months. The primary end point was time to castration resistant prostate cancer (CRPC). The types of ADT were monotherapy and maximal androgen blockade (i.e., luteinizing hormone-releasing hormone agonist and antiandrogen). RESULTS: The characteristics of patients showed no significant differences between the CADT and IADT groups, except for the Gleason score (p<0.001). The median time to CRPC of all enrolled patients with ADT was 20.60±1.60 months. The median time to CRPC was 11.20±1.31 months in the CADT group as compared with 22.60±2.08 months in the IADT group. In multivariate analysis, percentage of positive core (p=0.047; hazard ratio [HR], 0.976; 95% confidence interval [CI], 0.953-1.000), Gleason score (p=0.007; HR, 1.977; 95% CI, 1.206-3.240), lymph node metastasis (p=0.030; HR, 0.498; 95% CI, 0.265-0.936), bone metastasis (p=0.028; HR, 1.921; 95% CI, 1.072-3.445), and CADT vs. IADT (p=0.003; HR, 0.254; 95% CI. 0.102-0.633) were correlated with the duration of progression to CRPC. The IADT group presented a significantly longer median time to CRPC compared with the CADT group. Additionally, patients in the IADT group showed a longer duration in median time to CRPC in subgroup analysis according to the Gleason score. CONCLUSIONS: This study found that IADT produces a longer duration in median time to CRPC than does CADT.