Hormone therapy treats prostate cancer by lowering some hormones. These hormones are called androgens. Prostate cancer needs them to grow.

The main androgen is testosterone. Reducing it can slow the growth of the cancer. It can even shrink tumors.

The testicles are the main source of testosterone. Hormone therapy can be done in two ways.

• It is most often done with medicines. They stop the testicles from making testosterone or they block it.
• Less often, surgery is done to remove the testicles.

Both types of hormone therapy can cause serious side effects. These include a greater chance of osteoporosis, heart disease, and diabetes.

Hormone therapy may also be called androgen deprivation therapy (ADT). Or it may be called androgen suppression therapy.

Types of hormone therapy

Hormone therapy for prostate cancer can be done with medicines or surgery.

Common medicines include:

• LHRH agonists. These stop your testicles from making testosterone. At first they may cause a short rise in testosterone. This can cause problems like bone pain. LHRH agonists are given as shots or small implants under the skin. Depending on the medicine, you might get them every month or up to every 6 months.
• LHRH antagonists. These also stop the body from making testosterone. They do not cause the short rise in testosterone. They are given as a monthly shot or as a pill you take every day.
• Androgen synthesis inhibitors. These block enzymes that the body needs to make testosterone. So they can lower testosterone levels more than other treatments. They are taken as pills every day.
• Antiandrogens. These block male hormones that help cancer grow. They stop your cells from using the small amounts of testosterone that may still be in your body. Some can affect your liver enzymes, so you’ll get a blood test before starting them. You may have to stop using alcohol while taking them. They’re usually taken as a daily pill.

Surgery to remove the testicles (bilateral orchiectomy) is another way to reduce testosterone. The testicles make most of the body's testosterone. Removing them lowers testosterone levels immediately.

Surgery is the simplest and quickest way to reduce androgen levels. But the effects are permanent.

Side effects

The side effects of hormone therapy for prostate cancer depend in part on the type of therapy you have. Your doctor can tell you what to expect. In general, possible side effects include:

• Erection problems and reduced sex drive.
• Thin or brittle bones (osteoporosis).
• Increased risk for diabetes and heart disease.
• Weight gain, especially around the belly. The medicines may raise your blood sugar (glucose) levels. If you have diabetes, you'll need to watch your blood sugar levels. Your doctor may adjust your diabetes medicines.
• Changes in appearance, such as thinning hair, smaller genitals, and larger breasts.
• Reduced muscle mass.
• Hot flashes.
• Fatigue.
• Mood swings.
• Liver problems.

Some of the side effects of hormone therapy medicines may last for 1 to 6 months after you stop taking the medicine. Side effects may last longer for people who are older or people who have used this treatment for a longer time. Surgery (bilateral orchiectomy) may cause similar side effects, but any side effects will be permanent.

Be sure to tell your doctor about any problems you have. Treatment and healthy lifestyle changes can help with some side effects. For example, exercise can help prevent bone density loss and help lower cholesterol and blood sugar levels. It can also help prevent weight gain and reduce fatigue during treatment. If you’re able, you might try walking up to 30 minutes a day for 3 to 5 days a week.