Hormone therapy is a treatment for cancer that reduces hormone levels or blocks their action and stops cancer cells from growing. A substance produced by glands in the body and circulated in the bloodstream, hormones can cause certain cancers to grow. If tests show that the cancer cells are hormone-responsive, drugs can be used to reduce the production of hormones or block them from working.
The most important hormone in prostate cancer is testosterone.
Hormone therapy is not expected to cure prostate cancer. As a primary treatment, hormone therapy may stop or even reverse the growth of a cancer, though not forever. It is often used as a treatment for advanced cancers.
Hormones may also be used as an adjuvant therapy if a cancer recurs, or as a neoadjuvant before another type of treatment aimed at curing the disease, such as radiation.
There are several types of hormone therapy used to treat prostate cancer, which may be combined to achieve the best outcome. They include the following:
- Luteinizing hormone-releasing hormone agonists can prevent the testicles from producing testosterone. Examples include leuprolide, goserelin.
- Antiandrogens can block the action of androgens, which are hormones that promote male sex characteristics. Examples include flutamide (marketed as Eulexin and Drogenil) and bicalutamide (marketed as Casodex).
- Drugs that can prevent the adrenal glands from making androgens include ketoconazole (marketed as Nizoral) and aminoglutethimide (marketed as Cytadren).
- Orchiectomy, or castration, is a surgical procedure to remove both testicles, the main source of male hormones, to decrease hormone production. This is not a common treatment.
- Estrogens, the hormones that promote female sex characteristics, can prevent the testicles from producing testosterone. However, estrogens are seldom used today in the treatment of prostate cancer because of the risk of serious side effects.
Side effects of hormone therapy can include hot flashes, impaired sexual function, loss of desire for sex, and weakened bones.