Luteinizing hormone-releasing hormone agonists in the treatment of men with prostate cancer: timing, alternatives, and the 1-year implant

Abstract

This article reviews the evidence underlying hormone treatment decisions for men with advanced prostate cancer. Luteinizing hormone-releasing hormone (LHRH) analogs are the mainstays of therapy, but 3 areas of LHRH use need clarification: (1) when to start therapy, (2) what alternatives are available, and (3) how to incorporate a long-term strategy for the individual patient. The Medical Research Council (MRC) study, a randomized clinical trial in 938 patients, shows that immediate hormone therapy in men presenting with advanced prostate cancer (stage > or =T3) imparts a survival advantage over a delayed-treatment approach (7.5 years vs 5.8 years, P = 0.0003). LHRH analogs are also widely used (1) along with definitive radiation therapy, (2) when positive lymph nodes are found after radical prostatectomy, and (3) when prostate-specific antigen increases after any primary treatment (biochemical failure). In these situations, timing of therapy is somewhat controversial. Several new developments in hormone therapy are noteworthy, including high-dose antiandrogen monotherapy, a LHRH antagonist (abarelix), transdermal estrogens, and a subcutaneous implant that releases leuprolide acetate at a constant rate for 1 year (Viadur; Bayer Corporation, West Haven, CT). With 4 years of clinical experience with Viadur now available, the long-term data indicate continued, uniform testosterone suppression into the castrate range and a high degree of patient satisfaction. Thus, a long-term strategy-permitting increased patient freedom and decreased dependence on a fixed injection schedule-has for the first time become possible with the Viadur implant in men requiring hormone therapy for prostate cancer.