Long-Lasting Antiandrogen Withdrawal Syndrome in Castration-Resistant Prostate Cancer: Three Cases With Complete Response

This is a case report of 3 patients who had a dramatic and long-term complete response after antiandrogen withdrawal. All 3 patients were diagnosed with advanced or metastatic prostate cancer with a high prostate-specific antigen (PSA) level. For all patients, we started combined androgen blockade as androgen deprivation therapy and the PSA concentration decreased to <0.1 ng/mL, but then started to increase. After discontinuation of antiandrogen the PSA concentration decreased again and has remained below the limit of sensitivity for more than 1 year in all 3 patients.

Effects of statin use on the response duration to androgen deprivation therapy in metastatic prostate cancer

PURPOSE: To determine whether statin use delays the development of castration-resistant prostate cancer (CRPC) in patients with metastatic prostate cancer treated with androgen deprivation therapy (ADT). MATERIALS AND METHODS: A total of 171 patients with metastatic prostate cancer at the time of diagnosis who were treated with ADT between January 1997 and December 2013 were retrospectively analyzed. The patients were classified into two groups: the nonstatin use group (A group) and the statin use group (B group). Multivariate analysis was performed on statin use and other factors considered likely to have an effect on the time to progression to CRPC. RESULTS: The mean patient age was 67.1+/-9.1 years, and the mean follow-up period was 52 months. The mean initial prostate-specific antigen (PSA) level was 537 ng/mL. Of the 171 patients, 125 (73%) were in group A and 46 (27%) were in group B. The time to progression to CRPC was 22.7 months in group A and 30.5 months in group B, and this difference was significant (p=0.032). Blood cholesterol and initial PSA levels did not differ significantly according to the time to progression to CRPC (p=0.288, p=0.198). Multivariate analysis using the Cox regression method showed that not having diabetes (p=0.037) and using a statin (p=0.045) significantly increased the odds ratio of a longer progression to CRPC. CONCLUSIONS: Statin use in metastatic prostate cancer patients appears to delay the progression to CRPC. Large-scale, long-term follow-up studies are needed to validate this finding.

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.