Medicines can be used to adjust the levels of testosterone in a process called hormonal manipulation, or androgen deprivation therapy (ADT). Since prostate tumors require testosterone to grow, reducing the testosterone level is often effective in preventing further growth and spread of the cancer. Hormone manipulation is mainly used to relieve symptoms in men whose cancer has spread.
Hormone manipulation can be achieved through the use of drugs, or surgically using a procedure called an orchiectomy. During an orchiectomy, the testicles are removed though an incision in the scrotum.
Drugs are also used to treat advanced prostate cancer by blocking the production of testosterone. These drugs must be given by injection, usually every three to six months. The procedure is sometimes called chemical castration, because it has the same result as surgical removal of the testicles. However, unlike surgery, the hormonal manipulation can be reversed if necessary.
Other medications used for hormonal therapy include androgen-receptor blocking agents. These medications prevent testosterone from attaching within prostate cells and activating cancer growth.