Combined androgen blockade in advanced prostate cancer: looking back to move forward.

In 1989, Crawford and colleagues suggested that combined androgen blockade with castration plus antiandrogen therapy provided significantly improved survival compared with castration alone. Since then, some studies have supported these results, whereas others have not. To resolve this discrepancy, the Prostate Cancer Trialists' Collaborative Group conducted a metaanalysis of 27 randomized trials to evaluate whether combined androgen blockade has benefits compared with castration alone. The results published in 2000 showed that combined androgen blockade using a nonsteroidal antiandrogen treatment (nilutamide or flutamide) improved survival compared with castration alone, whereas combined androgen blockade using a steroidal antiandrogen agent (cyproterone acetate) reduced survival compared with castration alone. In 2004, an analysis was carried out to evaluate the nonsteroidal antiandrogen agent bicalutamide in the combined androgen blockade setting, by incorporating the data from a trial of combined androgen blockade with bicalutamide versus combined androgen blockade with flutamide with the Prostate Cancer Trialists' Collaborative Group metaanalysis data for combined androgen blockade with flutamide versus castration. This analysis showed that combined androgen blockade with bicalutamide was associated with a 20% reduction in the risk of death compared with castration alone. The survival benefit associated with combined androgen blockade using a nonsteroidal antiandrogen agent should be weighed against the potential for increased toxicity and expense compared with castration alone. Studies have shown that bicalutamide has a better tolerability profile than flutamide or nilutamide. Furthermore, cost-benefit analyses of combined androgen blockade with bicalutamide suggest it is a cost-effective option versus castration alone and versus combined androgen blockade with flutamide. In summary, the present evidence suggests that combined androgen blockade with a nonsteroidal antiandrogen agent should be a first-line therapy option in patients with advanced disease.