Hormone therapy is used to treat advanced stage prostate cancer or cancer that has returned after localized therapy
Testosterone is an androgen, or male hormone, that is produced mainly by the testicles and in smaller amounts by the adrenal glands. It is responsible for the development of male sexual characteristics and it stimulates prostate growth. Prostate cancer cells also need testosterone to grow.
Hormone therapy lowers the levels of androgens, especially testosterone, either by blocking testosterone production or by blocking signals from the brain that stimulate testosterone creation. Hormone therapy is not a cure but research shows that it can help shrink prostates by up to 90 per cent. It also lowers PSA, sometimes to undetectable levels.
Unfortunately, in most cases the effects are temporary because not all prostate cancer cells depend on hormones to survive. Hormone therapy can be effective for as little as six months and as much as 10 years.
Treatment is usually continued at least until there is evidence of hormone-resistant disease (in other words, PSA levels continue to rise despite treatment). Whether to continue drug-based hormonal therapy after the PSA starts to rise again is an individual decision.
Hormone therapy can be done through medical castration (drugs that block the production or effects of hormones) or orchiectomy (surgical removal of the testicles). The most common types of hormonal therapy are:
LHRH Analogues The most common hormone therapy is luteinizing hormone-releasing hormone (LHRH) analogues or agonists. These drugs are injected (either monthly or every three to four months) into the body and block the brain signals that tell the testicles to make testosterone. About 10 days after they are injected, they stop almost all testosterone creation. There are four different types of LHRH Analogues available in Canada.
Orchiectomy Orchiectomy (surgical removal of the testicles) is the most direct and least expensive way to lower testosterone levels. The mere thought makes most men cringe, but this is a quick and relatively painless option for men who are unable or unwilling to use drug therapy. Orchiectomy is usually an outpatient procedure, under local anesthetic. In some cases, the contents of the testicles are removed but the shell remains. Testicular prosthetics (cosmetic testicular replacements) can also be implanted.
Anti-Androgens Anti-androgens (also called androgen receptor antagonists) do not stop the production of androgens. They block the effects of androgens circulating in the blood by preventing them from binding to their targets. Even after orchiectomy or LHRH analogue therapy, a small amount of male hormone is still produced by the adrenal glands. Anti-androgens can block the effect of these hormones. Anti-androgens are taken in pill form, one or three times per day.
Intermittent Therapy Intermittent therapy means starting and stopping hormone therapy at different times. Hormone drug treatments can be stopped when PSA drops to a certain level and then started again when it rises. Another type of intermittent therapy involves using hormone therapy for fixed periods of time (ex. six months on, six months off).
Intermittent therapy allows men to take a break from the side effects. Sexual function in particular can return when a man is off the drugs. However, it is not clear whether intermittent therapy is better at controlling the cancer than ongoing treatment.
Adjuvant / Neoadjuvant Therapy Hormone therapy can be used to enhance other treatments. When hormone therapy is given before surgery or radiation it is called neoadjuvant therapy. When it is used after surgery or radiation it is called adjuvant therapy.
When researchers first discovered that hormone therapy before surgery shrunk tumours, there was a lot of interest in neoadjuvant therapy. However, follow up studies showed that neoadjuvant therapy for three months before surgery doesn’t increase a man’s chances of a cure; in fact, it may have the opposite effect. Studies are being done to find out if hormone therapy for a longer period of time may benefit patients. At this time though, men should not take hormonal therapy before radical prostatectomy.
Hormonal therapy both before and after radiation therapy can benefit patients with advanced prostate cancer. Patients with advanced localized prostate cancer receiving external beam irradiation are usually treated with both neoadjuvant hormonal therapy (for three months) and adjuvant hormonal therapy (for two to three years). In patients in the early stages of the disease, who are candidates for brachytherapy, hormone therapy has not been shown to have any impact.
Side Effects Loss of Interest in Sex / Impotence Treatments available for erectile dysfunction include Viagra, Levitra and Cialis. These drugs will not work if the nerves that control erection are removed or damaged during local treatment. If nerves are damaged, penile implants can be used. Hot Flashes Hot flashes are very common and can vary from mild to quite severe. They make a man feel hot and then cold, even in neutral temperatures, and can cause sweating. Hot flashes can be easily controlled with low doses of estrogen or progesterone-like drugs, in pill or patch form. Breast Swelling and Tenderness Breast swelling and tenderness can be avoided by giving a low dose of radiation to the breast tissue before hormonal therapy is started. If symptoms are severe, the tissue can be irradiated to reduce discomfort. Osteoporosis In osteoporosis, bone density is reduced, making the patient more prone to fractures. The risk of osteoporosis may be reduced by taking calcium and vitamin D supplements, engaging in regular physical activity (particularly weight-bearing exercise) and taking bisphosphonates (drugs that strengthen bone). Weight Gain and Loss of Muscle Mass Men on hormonal therapy often gain weight in their mid section and can lose muscle mass due to the lack of testosterone. Weight-bearing exercise helps keep weight down and increases muscle mass. Other Side Effects Men who are on hormonal therapy may experience gradual personality changes over time. They may notice a decrease in energy and depression (usually mild) is common. Mood swings are common, although this effect is more pronounced in some men than in others. Antidepressants and/or counseling may help manage some of these side effects.