Hormone therapy for metastatic prostate cancer
A key treatment for metastatic prostate cancer. Hormone therapy helps slow the cancer and ease symptoms for many years.
Hormone therapy is the main treatment for metastatic prostate cancer and most men with metastatic prostate cancer will stay on hormone therapy. Hormone therapy aims to control the cancer and improve any symptoms such as poor urine flow or bone pain. Hormone therapy can work well for many years as a treatment for metastatic cancer. It can be used alone or with other treatments.
How does hormone therapy work?
The male hormone testosterone can help prostate cancer cells to grow and spread.
- Testosterone is a hormone
- Hormones control how normal cells grow and work.
- Testosterone is produced mainly in the testes. Small amounts are also produced in the adrenal gland.
- Hormone therapy is a treatment designed to stop the cancer cells getting the testosterone (androgen) they need to grow.
Hormone therapy can slow the growth of metastatic prostate cancer by:
+ Interfering with the production of testosterone
+ Stopping the testosterone from getting to the prostate cancer cells
Another name for hormone therapy is androgen deprivation therapy (ADT). Androgens are male hormones, so androgen deprivation means depriving the cancer cells of the male hormones that help them to grow.
How is hormone therapy given?
All hormone therapies aim to prevent male hormones from helping the cancer to grow, but the different drugs work in different ways.
Injections to help stop your body making testosterone.
Some drugs work by stopping male hormones being made in your testicles. These drugs are injected under your skin or into a muscle. Examples include goserelin (Zoladex®), leuprorelin (Prostap®), triptorelin (Decapeptyl®), leuprorelin acetate (Eligard®) and degarelix (Firmagon®).
Injections can be given once a month or every 3, 6 or 12 months. The amount of hormone therapy you get is the same, however often you have the injections. This is because some of the injections are ‘slow release’ and give you the medication slowly over a longer period of time. This might save you from having to make more trips to your GP to have the injection.
You might find that your testicles become smaller in size once you have been on hormone therapy injections for a while.
Tablets to stop testosterone being produced or to block the effect of testosterone so it doesn’t help the prostate cancer cells to grow.
Some drugs can block testosterone from entering prostate cancer cells. This prevents testosterone from helping the cancer cells to grow. These drugs are called anti-androgens and are given as tablets that you take at home. For example, enzalutamide (Xtandi®) and bicalutamide (Casodex®).
Other tablets help to stop the production of testosterone in your body. For example, abiraterone (Zytiga®). You may have to take a steroid tablet with some treatments. Your doctor will advise you on this.
Sometimes a combination of the injections and tablets may be used. This is known as combination therapy or complete androgen blockade (CAB) or maximum androgen blockade (MAB).
Combination therapy prevents testosterone being made in your testicles and also blocks the small amount of testosterone that is made by your adrenal glands from working on prostate cancer cells.
Tumour flare
When you start injection hormone therapy, you will probably be asked to take anti-androgen tablets for a week or two before your first injection. This is because with most hormone therapy drugs, your body’s first response to the injection is to try to make more testosterone. This could make your cancer grow more quickly and is known as ‘tumour flare’. The tablets block the effect of the testosterone and stop this from happening.
Side-effects of hormone therapy
Hormone therapy can cause side-effects because of the drop in testosterone. These may include:
These affect more than half the men who get hormone therapy. You may find them difficult to cope with. Get some advice on how to manage hormone changes.
This can vary from mild tenderness, with or without swelling, to more noticeable tissue growth around the breast area.
Bones can become more brittle and more likely to break (fracture). Read more about bone health.
You may gain weight, particularly around your waist. Your muscle tone and strength can also be reduced.
Extreme tiredness is a common side-effect. Fatigue can affect your energy, mood and concentration. Read more about fatigue and ways to manage.
Less testosterone can lead to mood changes, poor concentration or memory problems, anxiety and sometimes depression. Therapies like relaxation therapy, meditation or yoga, might help you to cope with these frustrating symptoms or counselling might help. Try your local cancer support centre for helpful therapy classes and free counselling.
Hormone therapy can have a big impact on your sex life. Because hormone therapy reduces the male sex hormone testosterone, it can affect your interest in sex (libido) and your ability to get an erection.
Libido may come back once you stop taking hormone therapy, although it can take many months. Read more about sex and prostate cancer.
How will I know if it’s working?
While you are on hormone therapy you will have regular check-ups, including regular PSA tests. Hormone therapy usually controls prostate cancer growth for many months or years. It is hard for doctors to predict for how long it will work because it depends on a number of factors. For example, how much cancer is present and the grade of your cancer.
PSA level
Your PSA level usually falls when you start hormone therapy. If your PSA level goes up on a few occasions, it may be a sign that your hormone therapy is not keeping the cancer under control as well as it had been. If this happens, your doctor will discuss which treatment options are open to you. For example, he or she may give you extra treatments or try a new type of treatment.
Testosterone level
Your doctor may test the level of testosterone in your body, to check the hormone therapy is adequately blocking its production.
Other treatment options
If your PSA level goes up on a few occasions, it may be a sign that your hormone therapy is not keeping the cancer under control as well as it had been. This is called becoming castrate resistant. If this happens, your doctor will discuss which treatment options are open to you. For example, he or she may give you extra treatments or try a new type of treatment.
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