Antiandrogen monotherapy: indications and results

Abstract

Many patients with prostate cancer for whom hormonal therapy is indicated are still physically and sexually active; quality of life is therefore a vital issue when considering treatment options. Traditional castration-based therapies, although effective, have implications with respect to quality of life, causing loss of libido, impotence, fatigue, and reduced bone mineral density. Monotherapy with a nonsteroidal antiandrogen is an attractive therapeutic alternative to castration, offering effective therapy with potential quality-of-life benefits. Of the available nonsteroidal antiandrogens, bicalutamide has been most extensively evaluated in the monotherapy setting. Mature combined data (56% mortality) from 2 large randomized studies show no statistically significant difference in overall survival between bicalutamide 150-mg monotherapy and castration in patients with locally advanced, nonmetastatic (stage M0) disease. Survival outcome in patients with metastatic (stage M1) disease (43% mortality) favored castration, although the difference in median survival between the groups was only 6 weeks. Bicalutamide 150-mg monotherapy was associated with significant advantages compared with castration, in terms of sexual interest and physical capacity, in patients with either M0 and M1 stage disease. Data from a small subgroup of patients with stage M0 disease suggest that bicalutamide may also reduce the risk of osteoporosis compared with castration. Long-term therapy with bicalutamide 150-mg monotherapy is generally well tolerated, with a predictable side-effect profile. The most common side effects are male breast pain and gynecomastia. Emerging evidence also supports the use of bicalutamide 150 mg, both as immediate monotherapy and as adjuvant therapy in early stage (localized or locally advanced) prostate cancer.