Modern antiandrogenic therapy of patients with castration-resistant prostate cancer without metastases

Abstract

The prevalence of prostate cancer continues to increase worldwide. The effectiveness of androgen deprivation therapy for advanced prostate cancer has a time limit, after which castration resistance and disease progression are formed. A part of patients with castrate-resistant prostate cancer has no metastases (according to standard imaging methods). The main goal of treatment of these patients is to prolong the time before metastasis formation. This article presents a review of the current understanding of the molecular mechanisms underlying the inhibition of androgen-receptor signaling with enzalutamide, a second-generation androgen receptor antagonist, and the results of clinical studies of its efficacy and safety in castrate-resistant prostate cancer without metastases. It was determined that enzalutamide stimulates the expression of a new class of genes that are not regulated by dihydrotestosterone. It was found that, in addition to inhibiting androgen receptors, enzalutamide can act as a partial transcriptional agonist. Enzalutamide therapy has been shown to reduce the risk of tumor progression and death in patients with non-metastatic castrate-resistant prostate cancer and is well tolerated. Treatment with this drug increases the time before metastases appear, before the first use of subsequent anti-tumor therapy is necessary, and the period before prostate-specific antigen levels have progressed. Study of mechanisms induced by enzalutamide – inhibition of prostate cancer cells growth and activation of genes contributing to cancer development by enzalutamide-related androgen receptor – can help to clarify possible ways of resistance formation to this drug and possibilities of its overcoming with combined therapy.