Recent developments in endocrine treatment of prostate cancer

Cancer of the prostate gland is the most frequently occurring malignant lesion in men. Because most prostate cells depend on androgen for growth, removal of testosterone by either orchiectomy or medical castration using diethylstilbestrol or a luteinizing hormone-releasing hormone (LHRH) analogue is first-line treatment for patients with symptomatic Stage D2 disease. The trend in hormonal therapy has been toward long-acting minimal-dosing high-compliance regimens, capitalizing on the recent availability of the long-acting LHRH analogues, which require only monthly injections to maintain castration levels of testosterone, and the nonsteroidal antiandrogen ICI 176,334, which (in early clinical trials) appears to block intracellular testosterone activity with a once-a-day oral regimen. To eliminate the rapid LH increase that can occur during early agonist therapy, combinations of LHRH analogues and antiandrogens (total androgen blockade) have been tested and appear promising. The effects of hormonal treatment in patients with symptomatic Stage D2 prostate cancer have been studied extensively and are relatively well understood. By contrast, hormonal treatment has not been explored in contemporary randomized Phase III trials of asymptomatic Stage D2, D1, or C disease, localized Stage B or A disease, or before prostate surgery or radiation treatment. Research must continue to determine the optimal regimen that suppresses testosterone activity with the least amount of toxicity.