About hormone therapy for prostate cancer

Hormones occur naturally in your body. They control the growth and activity of normal cells. Cancer of the prostate depends on the male hormone testosterone for its growth. So lowering the amount of testosterone in the body can reduce the chance of an early prostate cancer coming back after treatment. Or it can shrink an advanced prostate tumour down or slow its growth. 

Sometimes hormone therapy can make advanced prostate cancer symptoms disappear completely. This kind of treatment usually works well for a few years. After that, the cancer often stops responding to the hormone treatment and starts to grow again.

How and when you have hormone therapy depends on the grade and stage of your cancer.

If you have a very early prostate cancer that can be cured with radiotherapy or surgery, and is at a low risk of coming back, you won't need to have hormone therapy.

You may have hormone therapy as well as radiotherapy to try to cure your cancer, if your doctor thinks there is a high risk of your cancer coming back because

• It has grown through the covering of the prostate (the capsule) (stage T3) or
• You had a very high prostate specific antigen (PSA) level when you were diagnosed or
• You have a high Gleason score.

Doctors usually recommend that you have the treatment for between 3 months and 3 years depending on the above factors and how many side effects you get. Some men have hormone therapy before and during the radiotherapy and others have it afterwards.

If your cancer has spread to another part of the body or it has grown too far into the tissue around the prostate gland to be successfully treated with surgery or radiotherapy, your doctor will suggest hormone treatment alone.

Testosterone is mainly made in the testes. Your testosterone levels can be reduced by medicines. They can also be lowered by surgery to remove the testes (orchidectomy). These days, you are more likely to have drug based hormone treatment than surgery. Surgery is usually only used to reduce testosterone levels urgently, if your cancer has spread to the bone and is pressing on your spinal cord (spinal cord compression). But it is an option that your doctors may suggest if you don't want to have treatment with medicines.

There are different types of drugs that reduce testosterone levels and they are called

• Luteinising hormone (LH) blockers – they include goserelin (also called Zoladex), buserelin, leuprorelin (also called Prostap), histrelin (Vantas) and triptorelin (also called Decapeptyl)
• Anti androgens – they include flutamide (also called Drogenil) and bicalutamide (also called Casodex)
• Gonadotrophin releasing hormone (GnRH) blocker – degarelix (Firmagon)
• Abiraterone

Luteinising hormone (LH) blockers

The testes make the male sex hormone, testosterone, because a hormone released by the pituitary gland in the brain tells them to. Luteinising hormone blockers stop the pituitary gland making the hormone. So the testes don't receive the message telling them to make testosterone. Examples of LH blockers include leuprorelin (Prostap), goserelin acetate (Zoladex), buserelin, triptorelin and histrelin (Vantas).

You have LH blockers as injections under your skin. Some are given monthly, some every 3 months, and some yearly. At first, the injections may make your symptoms worse. This is called tumour flare. Your doctor will give you an anti androgen tablet to take for the first 4 to 6 weeks of your treatment with the LH blocker to stop tumour flare.

Anti androgens

Anti androgen tablets stop testosterone from your testicles from getting to the cancer cells. So the cancer cells can't grow. Examples of anti androgens include

• Cyproterone acetate (Cyprostat) – the Committee on the Safety of Medicines in the UK recommend that this is not used long term
• Flutamide (Drogenil)
• Bicalutamide (Casodex)

The advice on not taking Cyprostat long term is because it can cause liver problems if you take it for a long time. There are circumstances when your doctor may still suggest that this drug may be a better option than other available treatments.

You take flutamide 3 times times a day. Some men find that flutamide gives them troublesome diarrhoea. If this is the case for you, talk to your doctor about it. There may be another treatment you can try or you may be able to take medicines to help with the diarrhoea.

If you have locally advanced prostate cancer you may be prescribed bicalutamide with radiotherapy. Locally advanced means that the cancer has either begun to spread outside the prostate gland or has spread into lymph nodes nearby. You take bicalutamide once a day.

Flutamide and high dose bicalutamide are less likely to cause erection problems and other side effects than leuprorelin (Prostap) or goserelin (Zoladex). But they are more likely to cause breast swelling and tenderness. There is information about hormone therapy side effects in this section

Gonadotrophin releasing hormone (GnRH) blocker

Gonadotrophin releasing hormone (GnRH) blockers work by blocking messages from the brain that tell the testicles to produce testosterone. There is currently only one GnRH blocker and it is called degarelix (Firmagon). You have it by injection just under the skin of the abdomen (tummy).

Degarelix does not cause tumour flare so you don't need to take anti androgen tablets. You have the injection once a month. When you first start the treatment you have 2 injections on the same day.

Abiraterone

Abiraterone is a new type of hormone therapy. It blocks an enzyme called cytochrome p17 that the body needs to make androgens. Without this enzyme the testes and other body tissue can't make testosterone. You can have abiraterone if you have advanced prostate cancer and have already had other types of hormone therapy and chemotherapy containing docetaxel that is no longer working.

It is a tablet you take every day.

There are different ways of using hormone therapy drugs for prostate cancer. You may have

• Luteinising hormone blockers on their own
• Anti androgens on their own
• A luteinising hormone blocker and an anti androgen together
• Gonodotrophin releasing hormone blocker on its own

It is most common to have either a luteinising hormone blocker or an anti androgen. Luteinising hormone blockers are generally thought to be more effective than anti androgens, but high dose bicalutamide (Casodex) is also sometimes used for locally advanced prostate cancer (stage 3 cancer). 

You may have LH blockers and anti androgens together for a short time to prevent tumour flare. You may also have them together if your cancer is showing signs of becoming resistant to one of the drugs taken on its own. Having both types of drug together is called complete androgen blockade (CAB) or maximal androgen blockade (MAB). CAB can be used to treat advanced prostate cancer if it has stopped responding to LH blockers on their own. It is given to try to slow the growth or spread of the cancer. But there are increased side effects if you take both types of drug together.

Some doctors prescribe hormone therapy for you to take all the time (continuously). Others prefer to give you a few months treatment, followed by a break. Then you have more treatment and so on. This is called intermittent treatment. Intermittent therapy gives reduced side effects but it may also control the cancer for slightly less time.

You will probably want to discuss the choice of hormone treatment with your doctor. There are benefits and drawbacks to each type of drug, so you may prefer to make a decision based on the side effects of the treatments.

If your cancer is advanced when it is diagnosed, you may start hormone therapy straight away. If you have no symptoms, your doctor may suggest keeping an eye on you and only prescribe treatment when you have symptoms that need treating. But there is some evidence that men live longer and complication rates are lower with early hormone therapy. So doctors sometimes suggest this approach. They may recommend any of the drugs mentioned above.

After some months or years, the cancer usually stops responding to the hormone treatment and starts to grow again. This is called hormone refractory prostate cancer. When the cancer starts to develop again, your doctor may suggest stopping the hormone therapy. In about 3 out of 10 men the cancer shrinks and stops growing for some months. Shrinking of the cancer after stopping hormone therapy is called an anti androgen withdrawal response (AAWR). Or your doctor may recommend treatment with chemotherapy or steroids.

There is information about research into hormone therapy in the prostate cancer research section.

UK Prostate Link can direct you to information about hormone therapy to treat prostate cancer.