Hormonal therapy may be given in addition to surgery or radiotherapy - this is known as adjuvant therapy. The aim is to reduce the chance of the cancer coming back.

Hormones control the growth and activity of normal cells. In order to grow, prostate cancer depends on the hormone testosterone produced by the testicles. Hormonal therapies reduce the amount of testosterone in the body. They can be given as injections or tablets.

Some drugs 'switch off' the production of male hormones from the testicles by reducing the levels of a hormone produced by the pituitary gland. These drugs are called pituitary down-regulators or gonadotrophin releasing hormone analogues (GnRH analogues). They include goserelin (Zoladex®), leuprorelin (Prostap®) and triptorelin (Decapeptyl®).

They are usually given as a pellet injected under the skin of the abdomen (goserelin), or as a liquid injected under the skin or into a muscle (leuprorelin or triptorelin). Injections are given either monthly or every three months.

Other hormonal therapy drugs work by attaching themselves to proteins (receptors) on the surface of the cancer cells. This blocks the testosterone from going into the cancer cells. The drugs are called anti-androgens and are often given as tablets. Commonly used anti-androgens are flutamide (Chimax®, Drogenil®), bicalutamide (Casodex®) and cyproterone acetate (Cyprostat®).

Anti-androgen tablets are also usually given for two weeks before the first injection of a pituitary down-regulator. This prevents tumour flare, which is where symptoms get worse after the first dose of treatment.

Research trials are being carried out to find out:

• whether it is better to start the hormonal therapy before or after the surgery or radiotherapy
• how long to give the treatment for (it can range from two months to two years).

Unfortunately most hormonal therapies usually cause erection difficulties and loss of sexual desire for as long as the treatment is given. If the treatment is stopped, the problem may disappear. Some types of anti-androgens are less likely to cause impotence than others.

In about half the men who have hormonal therapies the side effects that cause them the greatest problem are hot flushes and sweating. Flushes stop if the treatment is stopped. In the meantime some medicines can help. We can send you information about this.

Hormonal treatment can also make you put on weight and feel constantly tired, both physically and mentally. Some drugs (most commonly flutamide and bicalutamide) may also cause breast swelling and tenderness.

Different drugs have different side effects, so it is important to discuss the possible effects with your doctor before you start treatment. Being warned about possible side effects can make them easier to cope with.

We have sections about individual hormonal therapies, with more information about how the drugs work and tips on coping with possible side effects.