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General side effects of radiotherapy

Nurse and patients talking about cancer

This page gives an overview of the general side effects of radiotherapy. There is information about


Why radiotherapy causes side effects

Radiotherapy destroys cancer cells in the area of the body it is aimed at but it also affects some of the normal cells nearby. Radiotherapy affects people in different ways, so it's difficult to predict exactly how you will react. Some people have only mild side effects but for others the side effects are more severe.


Finding out about side effects

Before you start your treatment, talk about any likely side effects with the staff in your radiotherapy team. Knowing about the side effects may help you to prepare and to manage any problems. Ask about any possible long term side effects that the treatment may cause.


Side effects during treatment

Most people feel tired while they are having radiotherapy, particularly if they are having treatment over several weeks. This is because the body is repairing the damage to healthy cells. Or tiredness can be due to low levels of red blood cells (anaemia). Rest if you need to and try to exercise a little when you can, as this may help to reduce the tiredness. There is information about coping with tiredness in the coping physically section.

You may have other general symptoms, such as feeling weak or as if you are coming down with flu, for a few days after you have had radiotherapy.

Some people get sore skin in the area being treated. We have information about preventing and dealing with skin soreness.

Radiotherapy makes the hair fall out in the treatment area. Hair in other parts of the body is not affected. The hair should begin to grow back again a few weeks after the treatment ends. There is information about coping with hair loss in our coping physically section.

Other side effects will depend on the area of the body being treated.

Tell your doctor, nurse or radiographer about any side effects that you have. They can give you leaflets which describe the side effects. They can also help you find ways of reducing the effects and coping with them.


Possible long term side effects

For many people the side effects of radiotherapy wear off within a few weeks of the treatment ending and they can go back to a normal life. But for some people radiotherapy can cause long term side effects. The possibility of long term side effects can depend on the type of cancer and its size and position. It may also depend on how close the cancer is to nerves or other important organs or tissues.

It is important to ask your doctor and specialist nurse about the possibility of long term side effects, such as a change in skin colour in the treatment area, a dry mouth, breathing problems, infertility, impotence, or long term soreness and pain. Our pages about radiotherapy to particular areas of the body discuss the possible long term side effects of

You can also find out more in the radiotherapy section for each type of cancer.

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Updated: 4 July 2012