Radiotherapy side-effects

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Any side-effects you get will depend on which part of your body is being treated and the number of treatments you get. Most side-effects are temporary and are rarely severe.

How long will side-effects last?

  • Short-term (acute) side-effects: Normally develop within 2 weeks of starting treatment. These usually last for a few weeks.
  • Long-term (chronic) side-effects: These are much less common. They may happen months to years after treatment and may sometimes be permanent.

Always tell your medical team as soon as possible if you notice any change in yourself or your normal routine, such as a change in diet, weight, sleeping habits, increased discomfort or pain.


Radiotherapy and fatigue

You may feel tired for some weeks or even months. Tiredness can build up over the course of your treatment, especially if you are travelling back and forth to the hospital. Most people recover from their tiredness within a couple of months of finishing treatment. 

We have information on fatigue and tips to help you cope.

Skin changes

  • Skin within the treatment area can become warmer, harder, sore, itchy, peel or flake, and/or become swollen.
  • For people with white skin tones, the skin within the treatment area may become pinker or redder before looking darker, like a tan.

  • People with brown and black skin tones can find their skin may go subtly darker (than their normal), have a maroon, purple, grey, or yellow appearance within the treatment area.

Skin reactions usually happen after 3 to 4 weeks of treatment. Your radiation therapists will check for any skin reactions during treatment, but you should also let them know straight away if you feel any soreness or have any other skin changes. Your doctor may prescribe a cream or lotion for you to use. Skin reactions usually settle down 2 to 4 weeks after treatment has finished. Your skin may stay little darker than the surrounding skin.

Your radiation therapist and nurse will give you advice on how to look after your skin during and after radiotherapy. You can also read our web page for information and tips on coping with skin changes.

Side effects by body area

Because radiotherapy is aimed only at the cancer, any side-effects tend to affect the area being treated. Read more about these possible side-effects:

What can I do to reduce side-effects?

To make sure that your radiotherapy works as well as possible and to reduce side-effects, it may help to stop smoking during treatment. Your doctor may recommend that you give up alcohol and smoking completely, especially if you are being treated for head and neck or lung cancers. 

It’s also important to eat a balanced diet and drink plenty of fluids during treatment to promote healing and good health.

For more information

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