Hormone therapy uses drugs that interrupt the body's mechanisms for producing hormones, and can slow down or stop the growth of cancers that, like prostate cancer, are hormone driven. Hormone therapy is intended to keep male hormones (testosterone) from getting to prostate cancer cells, thereby stimulating them to grow and spread. There are several types of hormone therapies, and they will be outlined below. Estrogens are effective hormone treatments, but are no longer used because of unacceptable side effects.
Surgical castration or removal of the testicles is the cheapest of the hormone treatments. However, it is disfiguring and irreversible. For patients who do not mind having this done, it may be preferable if permanent hormone ablation is recommended.
Hormone Analogues (LHRH Agonist)
LHRH agonists are given in the form of a shot. These shots can be administered every one to four months depending on how much medication is given. Examples of LHRH agonists include Leuprorelin Acetate (Lupron) and Goserelin Acetate (Zoladex). These medications act on the brain (pituitary gland), and block the release of a hormone that normally would go to the testicles and stimulate them to make testosterone. The testosterone level usually drops to the same very low level that it would after castration. This treatment is sometimes called "medical castration."
Anti-androgens are given in the form of a pill. Casodex is taken once a day. Flutamide must be taken three times each day. They block testosterone from getting to the cancer cells. In the case of castration and LHRH agonist therapy, small amounts of male hormones are still made in other organs such as the adrenal glands. Anti-androgens can stop the effects of these male hormones and, therefore, sometimes they are prescribed along with surgical or medical castration. Some patients are treated with anti-androgens alone without castration. The advantage of this is that most men can remain sexually active.
Side Effects of Hormone Therapy
Surgical and medical castration almost always causes loss of sex drive and impotence. Rarely are men sexually active and usually they do not care. Most men have hot flashes, which can be drenching and can interfere with sleep. Usually the hot flashes become less bothersome over time, but the sex drive does not come back as long as castration is in effect.
Other possible side effects include anemia, loss of bone (osteoporosis), changes in hair or skin, fatigue, loss of muscle mass, weakness, increase in body fat (usually around the waist) and breast enlargement (gynecomastia). Gynecomastia can be painful, but it can usually be prevented with tamoxifen or three radiation treatments to the breast. These treatments must be given before the breast enlargement occurs.
The anti-androgens, if given alone, have a very high probability of causing painful, enlarged breasts. It is strongly advised to give tamoxifen or breast radiation in this situation, and the treatment should be given before the anti-androgens are started. These medications can cause diarrhea or cramping. Rarely they can cause liver damage. Liver enzymes (liver function tests), a blood test, should be performed periodically.