First-line use of novel hormonal agents in prostate cancer: a critical appraisal

Castration has been the hallmark of the treatment of advanced prostate cancer for nearly a century. Conventional surgical or medical castration for the management of metastatic prostate cancer has been associated with an initial response rate greater than 60% to 70%, depending on the criteria employed. The median duration of the initial response is usually less than 3 to 5 years, however, depending on the extent of disease. The failure of disease to respond to castration has been associated with an increase in the production of adrenal androgens and/or the evolution of upregulated or mutated androgen receptors. Second-line hormonal treatment with adrenal inhibitors is sometimes used, but remissions usually last for less than a year. Extensive translational research has produced a series of second-line, multitargeted, hormonally active agents that inhibit androgen receptor function and/or multiple sites within the hypothalamic/pituitary/end-organ axis. Abiraterone and enzalutamide have been shown to be active in second-line or subsequent hormonal therapy for castration-resistant prostate cancer, and recent data have shown a substantial anticancer effect in initial therapy. The potential use of abiraterone and enzalutamide as initial therapy for advanced prostate cancer is the focus of this brief review, which emphasizes that new approaches should not become the standard of care until they have been validated in randomized trials. In addition, it remains unclear whether first-line treatment with chemohormones or new-generation hormones should be the current standard for all patients with newly diagnosed metastatic prostate cancer.