Intermittent versus continuous total androgen blockade in the treatment of patients with advanced hormone-naive prostate cancer: results of a prospective randomized multicenter trial. Effectiveness of adjuvant intermittent endocrine therapy following neoadjuvant endocrine therapy and external beam radiation therapy in men with locally advanced prostate cancer.
The aim of this study was to compare the efficacy of total intermittent androgen deprivation (IAD) versus total continuous androgen deprivation (CAD) for treating patients with advanced prostate cancer in a phase III randomized trial. A total of 68 evaluable patients with hormone-naive advanced or relapsing prostate cancer were randomized to receive combined androgen blockade according to a continuous (n = 33) or intermittent (n = 35) regimen. Therapeutic monitoring was assessed by use of serum prostate-specific antigen (PSA) measurements. Patients in the CAD and IAD groups were equally stratified for age, biopsy Gleason score, and baseline serum PSA levels. The outcome variable was time to androgen-independence of the tumor, which was defined as increasing serum PSA levels despite androgen blockade. Mean follow-up was 30.8 months. The 35 IAD-treated patients completed 91 cycles, and 19 of them (54.3%) completed > or = 3 cycles. Median cycle length and percentage of time off therapy were 9.0 months and 59.5, respectively. The estimated 3-year progression rate was significantly lower in the IAD group (7.0% +/- 4.8%) than in the CAD group (38.9% +/- 11.2%, P = 0.0052). Our data suggest that IAD treatment may maintain the androgen-dependent state of advanced human prostate cancer, as assessed by PSA measurements, at least as long as CAD treatment. Further studies with longer follow-up times and larger patient cohorts are needed to determine the comparative impacts of CAD and IAD on survival. To clarify the optimal duration and methods for adjuvant endocrine therapy after external beam radiation therapy (EBRT) in patients with locally advanced prostate cancer.
                Between 2001 and 2003, 215 patients with locally advanced prostate cancer were enrolled in the study. Patients were registered as primary candidates of the study and were treated with 6 months of LHRH agonist, with short-term of antiandrogen treatment for flare-up prevention. Patients with PSA levels below 10 ng/ml after the 6-month endocrine treatment were randomly divided into two arms. Then, a total dose of 72 Gy was given to the prostate. After 14 months of the protocol treatment, patients were treated with continuous androgen ablation (arm 1) or intermittent androgen ablation (arm 2).
                A total of 188 cases (87%) remained in the protocol. The median PSA level at entry was 25.3 ng/ml. The Gleason score was 2-6 in 32 cases (16%), 7 in 94 cases (48%), and 8-10 in 68 cases (35%). The median PSA level showed a remarkable decrease to 1.1, 0.2, and 0.1 ng/ml, after 6, 8, and 14 months of the protocol treatment, respectively. Of the 157 cases treated with EBRT, 153 cases (97.5%) had no biochemical failure in the mean follow-up of 17.3 months.
                The present study may reveal the possibilities of intermittent endocrine therapy after EBRT. However, the follow-up interval is short and little can be said about the results observed so far, exception of acute tolerance and patient acceptance of the protocol.
                Copyright (c) 2004 Wiley-Liss, Inc.