The role of hormonal treatment in prostate cancer

Androgens are endocrine secretions produced mainly by the testes under stimulation of the pituitary gland. They are also synthesized from the adrenal glands in both sexes and from ovaries in females. Luteinizing hormone (LH) produced by the anterior pituitary gland regulates the secretion of androgens from the Leydig cells in the testes. LH secretion is controlled by the hypothalamus via gonadotropin-releasing hormone (GnRH). Androgens play a major role in the development and maintenance of male sex characteristics. The primary and most well-known androgen is testosterone that is rapidly and irreversibly converted to dihydrotestosterone (DHT) in prostate by types 1 and 2 5α-reductase. Androgens stimulate the growth of both normal and cancerous prostate cells by binding to and activating the androgen receptor (AR), a protein that is expressed in prostate cells. Then, AR stimulates the expression of specific genes that cause prostate cells to grow. The role of androgens in prostate cancer was first established in 1941 by Huggins and Hodges. Since then androgen deprivation therapy (ADT) has become the standard of care for patients with advanced prostate cancer. In this chapter ADT and its use in prostate cancer will be discussed.