A 16-year clinical experience with intermittent androgen deprivation for prostate cancer: oncological results

Abstract

To present oncological results with intermittent androgen deprivation (IAD) in a single center. Between 1992 and 2008, 566 patients with prostate cancer (PC) were selected for a non-randomized study of IAD. Two hundred and eighteen patients had biochemical recurrence (BCR) after local treatment for PC and 348 patients had micro- or macro-metastatic disease. On-treatment period (ONTP) consisted of three-monthly injections of gonadatropin-releasing hormone (GnRH) agonist combined with daily oral androgen receptor antagonist. Off-treatment period (OFTP) was indicated when prostate-specific antigen (PSA) was <4 ng/ml. Criteria for resumption of hormonal therapy were PSA >20 ng/ml or clinical symptoms. Cancer specific survival curves were computed according to the Kaplan-Meier method. Median follow-up was 81 months (12-230). Median age was 74.7 years (52-92). Median Gleason score at diagnosis was 7 (3-9). Median initial PSA was 17 ng/ml (0.4-433). Cycle duration decreased progressively from 23 months for the 1st cycle to 10 months at 12th cycle. The number of patients who became hormone resistant was 182 (32%). Median cancer specific survival probability for the series is 12 (10.8-infinity) years. No previous treatment group showed a higher cancer specific survival probability (log rank test, CI 95%, P = 0.003) versus BCR group. Multivariate analysis of cancer specific survival demonstrates age, initial Gleason score and initial PSA level as significant factors affecting mortality (P < 0.05). Intermittent androgen deprivation is an acceptable treatment in different stages of PC. Duration of cycle decreased progressively during therapy. Age, Gleason score and PSA are factors predicting mortality.