The role of antiandrogen monotherapy in the treatment of prostate cancer.

The mainstay of hormonal therapy in prostate cancer has been medical or surgical castration, both of which are associated with loss of libido and impotence, and may not always be acceptable to the patient. Antiandrogen monotherapy is an alternative treatment option to castration. There are two types of antiandrogen, i.e. steroidal (cyproterone acetate, CPA), and nonsteroidal (bicalutamide, flutamide and nilutamide). Data comparing survival outcome with CPA and castration are limited and conflicting. Furthermore, CPA is associated with loss of libido and erectile dysfunction. Large phase III trials have established that monotherapy with bicalutamide 150 mg once daily provides a survival outcome that is not significantly different to that after castration in men with locally advanced, non-metastatic disease, while conferring significant advantages for sexual interest and physical capacity. Current data are inadequate to draw conclusions on the comparative efficacy of flutamide and castration, while nilutamide is not licensed for monotherapy. Recent data reveal that bicalutamide 150 mg given once daily in addition to standard care (radical prostatectomy, radiotherapy or 'watchful waiting') significantly delays the progression of early (localized or locally advanced) prostate cancer. Bicalutamide has a more favourable side-effect profile than the other antiandrogens and is more likely to promote compliance.