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If you prefer not to undergo surgical hormonal therapy, there are drugs which can stop the production of androgens. The most common drugs are LHRH agonists and LHRH antagonists. The aim of these drugs is to stop the growth of the tumour by chemical castration. How they do this varies for each group of drugs. Each drug is different in how it is applied. If you have a history of cardiovascular disease, your doctor will advise you to see a cardiologist before starting with hormonal drug therapy.
LHRH
The production of testosterone is regulated by the brain. The brain produces several hormones which help regulate other hormones. These are called releasing hormones. The specific releasing hormones of androgens are called luteinizing-hormone releasing hormones (LHRH). In prostate cancer treatment, drugs that affect LHRH are used to stop the production of androgens.
LHRH agonists
LHRH agonists stop testosterone production in the testicles. They are administered as a depot injection right under the skin or into the muscle. These injections can last for 1, 3, 6 or 12 months. Discuss with your doctor which option is best for you.
In the first days after the first injection, LHRH agonists increase your testosterone level before they decrease it. This is known as a flare. The increase in testosterone level can cause the tumour to swell. In rare cases, this could be dangerous and can cause difficulties urinating. Your doctor might give you a low dose of anti-androgen drugs to prevent damage from rising testosterone levels.
LHRH antagonists
LHRH antagonists are a new form of hormonal drug therapy. They do not need to be combined with an anti-androgen for the first weeks because they do not cause a flare. Degarelix is the most commonly used LHRH antagonist. It needs to be administered every month by injection under the skin.
Anti-androgens
Anti-androgens block the action of testosterone. As a result, the tumour will grow slower or stop growing completely.
The most commonly used anti-androgens are cyproterone acetate, flutamide, and bicalutamide. They all come as a pill, and are taken every day.
Cyproterone acetate is usually administered in two or three daily dosages. Flutamide is administered three times a day. Bicalutamide is the most common anti-androgen, and it is taken once a day.
