Androgen deprivation therapy: a primer on concepts and therapeutic options

Prostate cancer is a cause of significant morbidity and mortality in men. Endogenous levels of androgen, produced by the testis and adrenal gland, have a complex and controversial role in the development and progression of prostate cancer. Androgen deprivation therapy (ADT) is a common treatment for prostate cancer, particularly in metastatic tumor cases and in certain cases of locally advanced disease. This paper reviews the surgical and medical options used to produce androgen blockade. Bilateral orchiectomy is the historic gold standard with fewer side effects than medical castration, although currently less frequently utilized. Gonadotropin releasing hormone (GnRH) agonists are the most commonly used medications for achieving castration. Other medications include estrogens, GnRH antagonists, steroidal and non-steroidal anti-androgens and 5-alpha reductase inhibitors. The advantages and side effects of each type of medication are described. Intermittent therapy and continuous androgen deprivation is discussed. While intermittent ADT is currently experimental, there is accumulating evidence demonstrating satisfactory oncologic outcomes with decreased morbidity compared to continuous treatment.