Side effects of radiotherapy

As your course of treatment progresses, you may find you become more tired than usual. 

You may need to reduce the hours that you work or cut back on social or sports activities. Make sure you get enough rest and accept offers of help with everyday tasks or jobs. If you are worried about anything, or would just like to talk, your doctor, radiographer or nurse will be happy to listen or advise.

The radiographer will check your progress regularly during your treatment and you will see the doctor or nurse from time to time in a clinic. If you have questions at any time, do ask.

There are many people in the hospital that may be able to help and support you: PALSpatient support groups, etc. If you would like to find out what services are available or how to contact a particular person, please ask.

Radiotherapy side effects

The side effects you may experience will depend on the part of the body that is being treated and how much treatment you have. Side effects only affect the part of the body that is treated. Everyone reacts to radiotherapy differently and many people have hardly any side effects. The radiographers will give you lots of support and advice to care for and manage the side effects.

You will also be given written information about the side effects relevant to your treatment. Most side effects are temporary and they are rarely severe. They may start at varying times during treatment and disappear in the weeks after the end of it. Some side effects may not start until treatment is finished.

Your doctor will discuss any possible temporary or permanent side effects with you before the start of your treatment and before you sign your consent form. Extra written information may be available.


Radiotherapy can make you feel more tired than usual. You should listen to your body and rest if you need to but continue your normal activities if you feel able. Some people are able to continue working but others find they are too tired. Tell your radiographer or doctor if tiredness is a problem. They may be able to offer advice on ways to save your energy and cope with everyday activities.

During your course of radiotherapy you may have regular blood tests to check the effects on your general health. If the radiotherapy causes anaemia, it may be necessary for you to have a blood transfusion.

Nausea and vomiting

A few people feel sick during radiotherapy – it depends on which part of the body is being treated. Some people feel sick at the beginning of a course of treatment but find that nausea often disappears within a day or two. Others start to feel sick later on.

Do tell the radiographers or your doctor if you suffer from nausea. You can be given drugs to control it and it’s very unlikely that your radiotherapy will need to be suspended. See coping with nausea for more information.

Eating and drinking

It is important to try to eat well during your treatment and also drink about two litres of fluid (three to four pints) each day. This may not be easy if you are nauseous, tired or spend a lot of time travelling to and from the hospital.

The dietitian can help you to plan your meals and can offer lots of hints about what to eat. Any of the team caring for you can contact the dietitian if you would like advice. See eating well when you have cancer for more information.

Hair loss

Radiotherapy can cause hair loss in the area being treated. Most hair loss is temporary and will start to grow back within two to three months of finishing treatment.

Sore skin

There is currently no general agreement based on research regarding caring for skin during radiotherapy. Advice on skin care varies from one hospital to another. The staff at your radiotherapy department will give you advice about how to care for your skin in the treatment area at the beginning of your course of radiotherapy.

During treatment the skin may become red and sore and it’s important not to irritate it. Avoid shaving within the treatment area. You may wash the area gently using a mild unperfumed soap, such as baby soap, and pat it dry. Don’t use any deodorants, perfumes or lotions on your skin other than those recommended by the team caring for you. You should protect your skin from extremes of temperature and continue using sunscreen (factor 15 or above) after your treatment has finished.

There has been little research into the effects of radiotherapy on different ethnic skin types. However, anecdotal evidence suggests that people with darker skin (for example, Asian or Afro-Caribbean) may develop greater skin reactions during treatment than people with lighter skin.

If you have any discomfort, the radiographers or nurses will advise you on skin care. The doctor may prescribe or suggest a cream or lotion for you to use. Swimming may not be advisable if you develop a skin reaction as the chlorine in the water may irritate your skin. If you do swim during treatment, make sure you rinse the skin well and apply aqueous cream. Discuss this with your doctor, radiographer or nurse.


You may find it more comfortable to wear loose, casual clothing made from natural fibres. If you have ink marks on your skin from your treatment, you may find they smudge onto your clothes. Stains can be removed from your clothes using a biological washing powder. However, you may wish to wear older or less special clothes during your treatment.

Joint or muscle stiffness

Occasionally people who have radiotherapy to areas over joints or muscles may experience some stiffness. This can occur at any time up to two years after treatment has finished. Regular exercise to these joints and muscles can prevent stiffness. Your doctor may refer you to a physiotherapist. If not, please ask for advice.

Late side effects

Any side effects which may develop in the longer term and which may be permanent depend on the part of your body that has been treated, the dose of radiotherapy you have received and many other things, such as why you are having radiotherapy. Your doctor will be able to explain these side effects and also the likelihood of them occurring. Do ask your doctor if you have any concerns.