Produced mainly in the testicles, male hormones, such as testosterone, cause prostate cancer cells to grow. Reducing hormone levels or blocking the cancer cells from using them can sometimes make the prostate cancer shrink or slow its growth.
The goal of hormone therapy is to lower the level of male hormones in the body or to stop the prostate cancer cells from using them. Hormone therapy does not cure the cancer and is often used to treat men whose cancer has spread or recurred after treatment.
There are several types of hormone therapy, including the following:
Orchiectomy. The surgical removal of the testicles to prevent the male hormones that stimulate growth of the prostate cancer from being produced.
LHRH (luteinizing hormone-releasing hormone) analogs. Drugs that decrease the amount of testosterone produced in a man's body by interfering with the normal chemical signals sent from the pituitary gland to the testicles. They are given as injections or as small implants under the skin. Drugs include Lupron, Viadur, Eligard, Zoladex, Trelstar, and Vantas.
LHRH antagonist. A drug that also lowers testosterone levels but may cause fewer problems when first given than LHRH analogs. It is given by injection under the skin. The only LHRH antagonist used at this time is Firmagon.
Anti-androgens. Substances that block the body's ability to use androgens (male hormones), because even after orchiectomy or LHRH-analog treatment, a small amount of androgens may still be produced in the body. Drugs include Eulexin, Casodex, and Nilandron. These drugs are taken daily as pills. They are usually used along with an LHRH analog or antagonist.
CYP17 inhibitor. A drug that stops other cells in the body from making small amounts of androgens. The main CYP17 inhibitor in use at this time is Zytiga. It is taken daily as a pill. It is most often used when other forms of hormone therapy are no longer working.
As each man's individual medical profile and diagnosis is different, so is his reaction to treatment. Side effects may be severe, mild, or absent depending on many factors, including the type of hormone therapy used. Be sure to discuss with your cancer care team any or all possible side effects of treatment before the treatment begins.
Possible side effects of hormone therapy for prostate cancer may include:
A degree of impotence (inability to achieve or maintain an erection)
Diminished libido (desire for sex)
Enlargement of the breasts
Loss of muscle mass
The duration of hormone therapy varies, depending on the individual situation and why it is being used. For men with locally advanced prostate cancer (cancer that has spread just outside the gland), long-term hormone therapy (at least two years) may control the disease better than short-term hormone therapy. For more advanced prostate cancer, hormone therapy may be used for as long as it continues to be effective. To help limit side effects, some doctors may prefer to give men a break from continuous treatment at times as long as the PSA level remains low. This is known as intermittent hormone therapy. Treatment is then started again if the PSA starts to rise or symptoms occur. Always talk with your doctor for more information on hormone therapy treatment.