External beam radiotherapy

External beam radiotherapy uses high energy X-ray beams to treat prostate cancer. The X-ray beams are directed at the prostate gland from outside the body. They damage the cancer cells and stop them growing.

You may be able to have radiotherapy if your cancer is still contained within the prostate gland (localised prostate cancer). Radiotherapy may also be suitable for some men whose cancer has spread to the area just outside the prostate (locally advanced prostate cancer).

External beam radiotherapy is sometimes given alongside permanent seed brachytherapy or temporary brachytherapy (internal radiotherapy). Radiotherapy can also be used after surgery if your PSA level starts to rise or if there is a risk that not all the cancer was removed with surgery.

What other treatments are available?


Watch Ally's story for one man's experience of radiotherapy treatment.

What are the advantages and disadvantages?

The advantages and disadvantages of radiotherapy will depend on your age, health and the stage of your cancer. Your specialist team will discuss your individual situation and options with you.

• Radiotherapy has none of the risks of surgery and having a general anaesthetic.
• It can be given when you are considered unsuitable or unfit for surgery.
• Some men may find the treatment position a bit uncomfortable but the radiotherapy itself is painless.
• It is relatively quick. Daily treatment sessions last about 10 to 20 minutes, and you do not need to stay in hospital overnight.
• You can carry on with many of your usual activities while you are having treatment.

• You will need to go to a specialist hospital for treatment five days a week for several weeks -- and each visit could take at least an hour. This might be difficult if you need to travel a long distance.
• There is a risk of side effects including bowel problems, urinary problems and erectile dysfunction.
• It may be some time before you will know whether the treatment has been successful.

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What does treatment involve?

You may be given hormone therapy for three to six months before you begin radiotherapy. This shrinks the prostate and makes the cancer easier to treat. You may also have further hormone therapy throughout your course of radiotherapy. Men who are at a higher risk of their cancer spreading may continue to have hormone therapy for at least two years after radiotherapy.

Before starting radiotherapy you will have scans to find the exact location, size and shape of your prostate. This is to make sure the treatment is accurate and that the surrounding areas do not receive more radiation than is necessary.   

You will have one treatment at the hospital every day from Monday to Friday, with a rest over the weekend to help your healthy cells to recover. You can go home after each treatment session and will not have to stay overnight. Treatment normally lasts between seven and eight weeks.

At the beginning of each treatment, the radiographer will move you into the right position on the treatment couch. The treatment then starts and the machine moves around your body. It does not touch you and you will not feel anything. The whole session lasts about 10 to 20 minutes, including the time taken to position you on the treatment couch.

Your PSA level will be checked, usually six to twelve weeks after your treatment has finished. It will then be checked regularly, often at least every six months for two years, and after that at least once a year. This is to monitor how well the radiotherapy has worked.

If your treatment has been successful your PSA level should drop. However, how quickly this happens, and how low the PSA level falls, will depend on whether you had hormone therapy alongside radiotherapy. If you had radiotherapy on its own, it may take up to two years for your PSA level to fall to its lowest level. If you had hormone therapy as well, your PSA level may fall more rapidly.

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What are the side effects?

Many men will get side effects during their treatment which only last a few weeks or months. However, some side effects can develop later and can become long term problems.

Possible side effects include bowel problems, urinary problems, tiredness and skin irritation. Longer term problems can include sexual problems and infertility. There is a small chance of other cancers developing, but this is very rare.

Side effects can often be treated, so if you have any unusual symptoms after having radiotherapy, ask your specialist team about it. Read our online fact sheet for more information on managing side effects.

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Questions to ask your doctor or nurse?

- How many radiotherapy sessions will I have?
- Will I have hormone treatment? Will this continue after the radiotherapy?
- What side effects might I get? Will these be temporary or permanent?
- Will I be able to continue as normal during the treatment (for example, go to work)
- How will we know how successful the treatment has been?
- If the radiotherapy is not successful, which other treatments can I have?
- Who should I contact if I have any questions at any point during my treatment?

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You can find a full list of references used to produce this page in our online fact sheet.