Before you have your first injection, you will be given a short course of anti-androgen tablets, typically Casodex. This is to prevent the body’s normal response to the first injection, which is to produce more testosterone. This rise in testosterone, known as a flare, could cause the cancer to grow more quickly for a short time. The anti-androgen tablets help to prevent this flare from happening. You will start taking the tablets a week or so before the first injection and continue taking them for a week or two afterwards. It is important that you take all of the tablets you have been given.
There are two different types of tablets that work in two different ways. These are anti-androgens and oestrogens.
Anti-androgens are drugs that work by stopping testosterone from reaching the cancer cells. Without testosterone the prostate cancer cells are not able to grow. This type of hormone therapy is taken as a tablet at least once a day. Anti-androgens can be used on their own, before having injections or together with an orchidectomy or LHRH agonists. You can ask your doctor how long you will need to take tablets for. Ask your doctor to tell you more about the drug that you have from the list below:
Bicalutamide (Brand name: Casodex)
Flutamide (Brand name: Drogenil or Chimax)
Cyproterone acetate (Brand name: Cyprostat)
The oestrogen drug diethylstilbestrol (previously called stilboestrol) can treat prostate cancer in two ways:
• It stops the brain from telling the testicles to release
• It acts directly on cancer cells, slowing their growth and
causing some cancer cells to die.
Taking diesthylstilbestrol tablets can increase your risk of circulation problems. Because of this, diethylstilbestrol is usually only used to treat advanced prostate cancer which is no longer responding to anti-androgens or LHRH agonists. You may not be able to take diethylstilbestrol if you have a history of high blood pressure, heart disease or stroke. Your doctor will advise you about this and can explain the potential risks and benefits. You will usually be given aspirin at the same time to reduce the risk of circulation problems.
Maximal androgen blockade
In some cases your specialist may suggest a way of using hormone therapy called ‘maximal androgen blockade’, also known as ‘combined androgen blockade’. This uses both
an LHRH agonist and an anti-androgen to treat the cancer.
Some specialists think that maximal androgen blockade slightly improves survival in men whose cancer has spread to other parts of the body (advanced prostate cancer). However, it may also increase the risk of side effects, so it is usually only used if single hormone therapies stop being effective.
Intermittent hormone therapy
Intermittent hormone therapy involves stopping treatment when your PSA level is low and steady and starting treatment again when your PSA starts to rise. Your doctor will advise you when you will start and stop treatment. The advantage of this method is that you may be able to avoid side effects during the time that you are not having treatment. However it can take six to nine months or sometimes longer for the side effects to wear off.
Researchers think that intermittent hormone therapy is just as effective at treating prostate cancer as continuous treatment, but this is still being tested in clinical trials. We do not yet fully understand all of the benefits and risks of this treatment method and it may not be suitable for all men.
See HORMONE THERAPY RISKS