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Side effects of radiotherapy

Find out about the side effects of external radiotherapy and how to cope with them.

Side effects tend to start a few days after the radiotherapy begins. They gradually get worse during the treatment. They can continue to get worse after your treatment ends. But they usually begin to improve after 1 or 2 weeks.

Everyone is different and the side effects vary from person to person. You may not have all of the effects mentioned.

Side effects can include:

Bladder and bowel problems

If you have radiotherapy to the vulva, it is not possible to completely protect some of the organs nearby. So the treatment may cause problems with your bowel or bladder.

Diarrhoea is a common side effect. Your doctor can give you anti-diarrhoea medicine to help control it. Drinking plenty of water is important while you have diarrhoea, because your body can become dehydrated quickly. 

You may get symptoms of sore bladder. This is called cystitis. You may feel you need to empty your bladder more often than normal. When you do pass urine, it may cause a burning sensation or be painful. This side effect usually gets better on its own. Drinking plenty of water can help. 

These are all acute side effects that should start to get better within a week or so of finishing your treatment. It is not impossible to get long term bladder and bowel problems after radiotherapy for vulval cancer, but it is rare.

Fertility and menopause

The vagina and ovaries are also affected by radiotherapy. If you are still having periods, your ovaries may stop working and you may have a premature menopause. If you do get this, it is likely to be permanent. This means that you will become infertile. Menopause can cause symptoms such as:

  • feeling emotional
  • hot flushes
  • sweats
  • dry skin and dry vagina
  • tiredness
  • anxiety and loss of confidence
  • thinning bones

These symptoms can be quite intense and can go on for a long time. Unfortunately, as with a natural menopause, it is not possible to predict how long they will last.

You may want to take hormone replacement therapy (HRT) to control your menopause symptoms. You can talk to your surgeon about this before your operation so that you can start HRT as soon as you have the surgery if you wish to. There is no medical reason why you shouldn't take HRT after having had vulval cancer. If you don't want to take HRT, there are suggestions for other ways to help control menopausal symptoms.

Your vagina may shrink and lose its ability to stretch (elasticity). You may also have vaginal dryness. Both of these are likely to be long term problems after radiotherapy to this part of the body. 

They can cause difficulty with sexual intercourse, which may become painful. There are different moisturisers and creams available to help with dryness. You may also find that using dilators helps to improve the stretchiness and make sex more comfortable. 

After your radiotherapy treatment has finished, your doctor will request to see you regularly afterward. This means you may need a physical examination each time. The dilators help keep your vagina flexible, so that these examinations are not painful. 

For more information about ways to cope with these symptoms and the types of treatment to prevent them, talk to your doctor and specialist nurse.

You are likely to feel very tired during your treatment. It tends to get worse as the treatment goes on. You might also feel weak and lack energy.

After a while you may need to sleep after each radiotherapy session. Rest when you need to.

Tiredness can carry on for some weeks after treatment has finished. But it usually improves very gradually.

Various things can help you to reduce tiredness and cope with it, for example exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.

You might feel sick at times. You can have anti sickness medicines. Let your treatment team know if you still feel sick, as they can give you other medicines.   

Your skin might go red or darker in the treatment area. You may also get redness or darkening on the other side of your body. This is where the radiotherapy beams leave the body. 

The red or darker areas can also feel sore. Your radiographers will give you creams to soothe the skin. The soreness usually goes away within 2 to 4 weeks of ending the treatment.

Tell the radiotherapy staff if you notice any skin changes.
Last reviewed: 
10 Feb 2016
  • External Beam Therapy
    Peter Hoskin
    Oxford University Press, 30 Aug 2012

  • Cancer and its management (7th edition)
    Souhami, R and Hochhauser, D
    Wiley Blackwell 2015

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