Hormone therapy for prostate cancer
The main purpose of hormone therapy for prostate cancer is to either lower the amount of hormones that are produced in a man’s
body, or stop the cancer cells from using these hormones. That’s why it is sometimes referred to as “androgen deprivation therapy” or “androgen suppression” therapy.
Certain male hormones—such as androgens that are primarily produced in a man’s testicles—can cause prostate cancer cells to grow. Testosterone is a type of androgen that affects the growth of prostate cancer cells.
While hormone therapy for prostate cancer may help slow down the growth of prostate cancer cells, or may shrink the cancer, it is not considered to be a cure. It is sometimes used before
surgery
and radiation, or in combination with
radiation.
It also may be used if surgery or radiation fail, and a man’s cancer comes back, or if a man’s cancer has spread outside the
prostate gland, and cannot be cured by surgery or radiation alone. That’s because it can target prostate cancer throughout the body.
Because prostate cancer often becomes resistant to long-term hormonal therapy (this is called hormone-refractory when it stop responding to any type of hormone therapy), treatment may be stopped for periods of time, and then started again. You may also hear the term "castrate resistant," which means cancer is still growing even when therapy is keeping testosterone levels at "castrate" levels, which are very low.
The effectiveness of hormone therapy for prostate cancer is usually monitored by
PSA testing.
Types of hormone treatment for prostate cancer
Luteinizing hormone-releasing hormone analogs/agonists: these drugs cause a drop in the amount of testosterone that is produced in the testicles. They are usually either injected with a needle or implanted under the skin. They are generally taken every month or at different intervals that can range from every 3 months to every year. This treatment is often referred to as "chemical castration."
Luteinizing hormone-releasing antagonists: this injected drug also works to stop the production of testosterone in the testicles, but works more quickly and do not cause a rise in testosterone levels (called tumor flares) that are associated with luteinizing hormone-releasing hormone agonists.
Antiandrogens: these are oral drugs (pills) that block a man’s body from being able to use androgens, such as testosterone. They may be used in combination with the other therapies. They may have fewer sexual side effects when used alone, according to the American Cancer Society.
Estrogens: these are also sometimes used, particularly if androgen deprivation therapy stops working (which happens sometimes). Estrogens stop testosterone from being produced in a man’s body, but they can cause breast enlargement and other potential health risks, such as blood clots.
P450 enzyme inhibitors: these work by blocking enzymes that prevent prostate cancer cells from making certain hormones, such as androgens. They may also be taken with the cortisone-like drug prednisone.
Some drugs that are commonly used to fight fungal infections, such as ketoconazole, may also be used to help block the production of androgens. Because it works quickly, it is more commonly prescribed for men just diagnosed with advanced prostate cancer, according to the American Cancer Society.
Another approach actually involves a surgical procedure called orchiectomy, where a man’s testicles are surgically removed.
There does not appear to be a clear consensus among physicians about when is the best time to start and stop hormone therapy for prostate cancer. More studies are needed.
Therapies are sometimes combined
More studies are needed, however, to determine whether it is better to treat men with a combined androgen blockage (antiandrogens in combination with androgen deprivation therapy such as luteinizing hormone-releasing hormone agonists or antagonists) than with antiandrogens alone.
Some physicians have suggested using a triple androgen blockage (antiandrogens plus a luteinizing hormone-releasing hormone agonist or antagonist, and a 5-alpha reductase inhibitor). But more clinical studies are needed to determine what combinations of hormone therapy for prostate cancer can be most effective.
Potential side effects
One side effect that can be frustrating (for both men and their loved ones) following hormone therapy for prostate cancer is that men may have little or no desire for sex.
Other side effects of hormone therapy for prostate cancer can include impotence, hot flashes, sore or swollen breasts, weight gain, tiredness, constipation, dizziness, and depression.
Diarrhea, nausea, and liver problems have been associated with antiandrogens. In addition to hot flashes, enzyme inhibitors (such as abiraterone), can cause joint or muscle pain, high blood pressure, fluid build-up, upset stomach and diarrhea.
Other medical problems that can develop include osteoporosis, anemia, and decreased muscle mass. Some studies have shown that the risk of cardiovascular problems, including high blood pressure, high cholesterol, and heart attacks can rise. A man’s risk of getting diabetes also may increase.
Thinking, concentration, and memory problems are other side effects that have not been well studied, but can be disconcerting. Age may also be a factor.
When men first use luteinizing hormone-releasing hormone analogs/agonists, they may experience a tumor flare. This may cause bone pain in men who have cancer that has spread to the bone, or spinal chord compression if the cancer has spread to the spine.
According to the American Cancer Society, hot flashes can often be helped by taking antidepressants. There are also several drugs to help prevent and treat osteoporosis. Brief radiation treatment to the breasts may help prevent enlargement. Exercise has also been shown to help fight fatigue, weight gain, and loss of bone and muscle mass.
Always discuss everything you read on this web site with a qualified medical professional.
Updated 3/12
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References:
The American Cancer Society. Prostate Cancer. http://www.cancer.org. Accessed March 29, 2012.
US TOO International, Inc. Pathways for new prostate cancer patients. http://www.ustoo.com. Accessed September 1, 2008. Bostwick DG, Crawford DE, Higano CS, Roach M, eds. American Cancer Society’s Complete Guide to Prostate Cancer. Atlanta, GA: American Cancer Society Health Promotions; 2005.