Combined androgen blockade for prostate cancer: review of efficacy, safety and cost-effectiveness.

A standard treatment for advanced prostate cancer is androgen deprivation by surgical or medical castration. In theory, however, combined androgen blockade (CAB) with an antiandrogen plus castration should be more effective because castration alone does not completely eliminate androgens in the prostate. Therefore, a number of randomized clinical trials (RCT) were conducted in the 1990s to investigate the efficacy of CAB with an antiandrogen (nilutamide or flutamide) plus castration; however, there were both positive and negative results for the efficacy of CAB. The lack of data on safety, quality of life (QOL) and cost-effectiveness has been a hindrance to the adoption of CAB for the treatment of prostate cancer. Nevertheless, discussion on CAB for the treatment of prostate cancer has continued for over 20 years, which suggests that there remains some hope for this regimen. In the 2000s, clinical research on CAB with the antiandrogen bicalutamide commenced. CAB using this new antiandrogen was found to prolong overall survival (OS) in patients with prostate cancer, with favorable safety profiles and cost-effectiveness, without deteriorating QOL. In this article, we discuss the feasibility of CAB with bicalutamide for the treatment of prostate cancer by reviewing the theoretical background of CAB and then the results of RCT conducted in the 1990s when the usefulness of CAB was assessed.