Prostate cancer needs testosterone to grow. Slowing the production of testosterone may slow the growth of the cancer or shrink it temporarily. This is called androgen deprivation therapy (ADT). This treatment used to be known as hormone therapy. ADT is often used before, during and after radiotherapy. It is also sometimes given with chemotherapy.
ADT is also used to manage advanced prostate cancer, when disease has spread beyond the prostate. In this case, the treatment will not cure the cancer but can keep it under control for months and even years. It may also reduce or eliminate the symptoms of cancer (temporary remission) and help with symptoms such as pain caused by the cancer spreading. ADT is given by injection, or in tablet form. In some cases, surgery to remove part or all of the testicles may be preferable.
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Injections of luteinising hormone-releasing hormone (LHRH) analogue and antagonist are used to control the production of testosterone.
These injections will not cure the cancer but will often slow its growth for years. LHRH agonist injections are usually given monthly, three-monthly or six-monthly.
Occasionally ADT is given in cycles. Treatment may continue until your PSA level is low, and then stopped for a period of time. It can then be restarted if your PSA rises again. This is not suitable for all men.
The advantage of intermittent ADT is that some side effects may be reduced while treatment is stopped. However, it can take many months after the last injection for any side effects to wear off. The risks and benefits of intermittent ADT are being tested in clinical trials and are not yet fully understood.
Tablets are called anti-androgens and work in a different way to injections to control cancer growth. They are used on their own but also with injections, known as a complete androgen blockade.
Surgery to remove all or part of the testicles offers a permanent solution for reducing testosterone levels. This is known as bilateral orchidectomy. Some men may prefer this approach over taking tablets or having regular injections.
- Bilateral orchidectomy – The removal of both testes. After surgery, men have the option of having silicone put into the scrotum to keep its shape.
- Subcapsular orchidectomy – The removal of only the inner part of the testes. This does not require a prosthesis.
Side effects of ADT
ADT may cause a range of side effects because of reduced testosterone levels. It is difficult to predict if or when a man’s testosterone will return to pre-treatment levels.
Side effects can include:
- reduced sex drive (libido)
- erection problems
- loss of muscle strength
- weight gain
- hot flushes
- breast growth and tenderness
- adverse cognitive and memory changes
- loss of bone density (osteoporosis) (your doctor may monitor your bone mineral density, calcium and Vitamin D levels)
- increased risk of other problems such as obesity, diabetes and heart disease (your doctor will assess these risks with you – it may be helpful to seek advice from a dietitian).
These side effects can be significant, but your doctor can help you minimise the impact.