Complementary and alternative therapies in prostate cancer

Complementary and alternative therapies are used with increasing frequency in men with prostate cancer. However, little is known about the efficacy of such therapies for this cancer. While epidemiological data support the association between intake of certain micronutrients with development of prostate cancer, there exist limited prospective data that support the chemopreventative or therapeutic value of such nutritional agents in prostate cancer. To date, one of the most studied treatments has been PC-SPES, a combination of eight herbal therapies with activity against prostate cancer. Studies in cell lines of human prostate cancer demonstrate significant dose-dependent decreases in cellular viability after exposure to extracts of this agent. Clinical studies suggested that PC-SPES could reduce prostate specific antigen levels in patients with either androgen-dependent or androgen-independent prostate cancer. Toxicity was mild, although there was a low risk of thromboembolic events with such treatment. Manufacture of PC-SPES was recently halted, after revelations that the herbal combination was contaminated with warfarin, which led to a recall by the manufacturer. Subsequent analyses also revealed the presence of diethylstilbestrol (DES) and indomethicin in some lots of PC-SPES. Available data regarding other alternative therapies are reviewed as well.