Single-therapy androgen suppression in men with advanced prostate cancer: A systematic review and meta-analysis

Purpose: To compare luteinizing hormone-releasing hormone (LHRH) agonists w ith orchiectomy or diethylstilbestrol, and to compare antiandrogens with an y of these three alternatives. Data Sources: A search of the MEDLINE, Cancerlit, EMBASE, and Cochrane Libr ary databases from 1966 to March 1998 and Current Contents to 24 August 199 8 for articles comparing the outcomes of the specified treatments. The sear ch was limited to studies on prostatic neoplasms in humans. Total yield was 1477 studies. Study Selection: Reports of efficacy outcomes were limited to randomized, c ontrolled trials. Twenty-four trials involving more than 6600 patients, pha se II studies that reported on withdrawals from therapy (the most reliable indicator of adverse effects), and all studies reporting on quality of life were abstracted. Data Extraction: Two independent reviewers abstracted each article by follo wing a prospectively designed protocol. The meta-analysis combined data on 2-year overall survival by using a random-effects model and reported result s as a hazard ratio relative to orchiectomy. Data Synthesis: Ten trials of LHRH agonists involving 1908 patients reporte d no significant difference in overall survival. The hazard ratio showed LH RH agonists to be essentially equivalent to orchiectomy (hazard ratio, 1.26 2 [95% CI, 0.915 to 1.386]). There was no evidence of difference in overall survival among the LHRH agonists, although Cls were wider for leuprolide ( hazard ratio, 1.0994 [CI, 0.207 to 5.835]) and buserelin (hazard ratio, 1.1 315 [CI, 0.533 to 2.404]) than for goserelin (hazard ratio, 1.1172 [CI, 0.8 98 to 1.390]). Evidence from 8 trials involving 2717 patients suggests that nonsteroidal antiandrogens were associated with lower overall survival. Th e CI for the hazard ratio approached statistical significance (hazard ratio , 1.2158 [CI, 0.988 to 1.496]). Treatment withdrawals were less frequent wi th LHRH agonists (0% to 4%) than with nonsteroidal antiandrogens (4% to 10% ). Conclusions: Survival after therapy with an LHRH agonist was equivalent to that after orchiectomy. No evidence shows a difference in effectiveness amo ng the LHRH agonists. Survival rates may be somewhat lower if a nonsteroida l antiandrogen is used as monotherapy.