Hormonal therapy keeps cancer cells from getting the male hormones they need to grow. It is called systemic therapy because it can affect cancer cells throughout the body. Systemic therapy is used to treat cancer that has spread. Sometimes this type of therapy is used to try to prevent the cancer from coming back after surgery or radiation treatment.

There are several forms of hormonal therapy:

• Orchiectomy is surgery to remove the testicles, which are the main source of male hormones.
• Drugs known as luteinizing hormone-releasing hormone (LR-RH) agonists can prevent the testicles from producing testosterone. Examples are leuprolide, goserelin, and buserelin. 
• Drugs known as antiandrogens can block the action of androgens. Two examples are Flutamide and bicalutamide. 
• Drugs that can prevent the adrenal glands from making androgens include Ketoconazole and aminoglutethimide.

After orchiectomy or treatment with an LH-RH agonist, the body no longer gets testosterone from the testicles. However, the adrenal glands still produce small amounts of male hormones. Sometimes, the patient is also given an antiandrogen, which blocks the effect of any remaining male hormones. This combination of treatments is known as total androgen blockade. Doctors do not know for sure whether total androgen blockade is more effective than orchiectomy or LH-RH agonist alone.

Prostate cancer that has spread to other parts of the body usually can be controlled with hormonal therapy for a period of time, often several years. Eventually, however, most prostate cancers are able to grow with very little or no male hormones. When this happens, hormonal therapy is no longer effective, and the doctor may suggest other forms of treatment that are under study.