Side effects of radiotherapy

Radiotherapy for cervical cancer can cause side effects. The side effects vary from person to person. You may not have all of the effects mentioned.

Side effects tend to start a week after the radiotherapy begins. They gradually get worse during the treatment and for a couple of weeks after the treatment ends. But they usually begin to improve after around 2 weeks or so.

Side effects include:

You might have diarrhoea during your treatment. This is normal but can be unpleasant. Tell the radiographers if you have diarrhoea and they will advise you how to manage it. 

You might find that you have some stinging when passing water. This is normal but not very nice. Tell one of the radiographers if this happens and make sure that you are drinking plenty of water and other fluids.

After internal radiotherapy, you may have some bleeding from the vagina after the applicators are taken out. This should clear up within 48 hours (2 days).

Tell your radiotherapy doctor or nurse if the bleeding becomes heavy or goes on for longer than this.

During your treatment the skin in the treatment area might become quite sore and red. This might include your vulva and the area around your back passage.

Use a moisturiser on the skin in the treatment area every day. This will help to keep the skin hydrated and more comfortable. Your radiographers will tell you which cream you should use. Don't use any other type of cream or lotion.

The skin reaction can look and feel like a burn but it is inflammation due to the radiation. It usually starts about 5 to 7 days into treatment and continues for about 10 days after your last treatment. It then starts to improve.

Ask your radiographers for advice on how to manage the sore skin. There are things you can do to make yourself more comfortable.

You might feel tired during your treatment. It tends to get worse as the treatment goes on. You might also feel weak and lack energy. Rest when you need to.

Tiredness can carry on for some weeks after the treatment has ended but it usually improves gradually.

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

Long term side effects

Most side effects gradually go away in the weeks or months after treatment. But some side effects can continue or might start some months or years later.  

Generally, radiotherapy can make body tissues become tighter and less elastic. Doctors call this fibrosis. It can have some lasting effects, depending on the part of the body being treated. For example it can cause thickening of the skin in the treatment area. 

If you have not already had the menopause, your radiotherapy will cause an early menopause. The radiotherapy stops the production of sex hormones by the ovaries. The hormone levels start to fall from about 3 months after the start of treatment. It is still important to use effective contraception during this time. 

Your periods gradually stop and you get symptoms of the menopause. The symptoms may be more severe than after a natural menopause. You can take hormone replacement therapy (HRT) after treatment for cervical cancer. There are gels and creams available that can help with vaginal dryness.

If you have already had your menopause, your ovaries will have stopped working before your treatment. So the radiotherapy won't make as much difference to you.

After your treatment your vagina can become narrower and less stretchy. You might also have vaginal dryness. This can affect your sex life.

Your doctor will need to do a physical examination of your vagina during your follow up appointments. To try to prevent or minimise narrowing and stiffening of the vaginal tissues, it is important to start using vaginal dilators after your course of radiotherapy treatment.

The dilators can help to make sure you can still have sex comfortably and have vaginal examinations. Your radiotherapy team will advise you how and when to start using dilators and suggest suitable lubricants to use.


Dilators are tube shaped objects, made of plastic or metal. They come in different sizes. You gently put the dilator into your vagina for 5 to 10 minutes about 3 times a week. This stretches the vagina and helps to stop it from narrowing. It is important to be gentle and not force this. 

You could switch to a smaller size if you find it difficult to get the dilator in. You might find it easier with a water soluble lubricant such as Astroglide, Durex lube or KY jelly. You can use the dilator in the bath if you prefer. You can also use a moisturiser such as Replens 2 or 3 times a week. 

If you find the dilator you have been using is getting a tighter fit, you may need to use it more often. You can talk to your doctor or nurse about this. You may have slight bleeding or spotting after using your dilator. This is normal.

However, it isn't normal to have heavy bleeding or pain. Contact your doctor or nurse If you have either of these.

You usually start using your dilator from anything between 2 and 8 weeks after your radiotherapy ends. This varies depending on your radiotherapy centre. Your doctor might advise you to use the dilators for 2 years or more, even if you are sexually active.

This is not a common side effect but sometimes one or both legs can swell if you have radiotherapy to the lymph nodes. Some people might have swelling of the genitals. This swelling is called lymphoedema. 

Tell your specialist straight away if you think either of your legs are getting swollen. You will need to be assessed by a lymphoedema specialist. The sooner it is diagnosed, the easier lymphoedema is to treat.

You may have some permanent effects from your treatment. This doesn't happen to everyone. It's difficult to predict who is going to have a problem. 

After any type of radiotherapy for cancer of the cervix, you might find that you have to pass urine more often. The treatment can make the bladder less elastic. So it won't stretch as far and feels full sooner. You may also be more prone to urine infections.

You might have some permanent bowel effects from your treatment. This doesn't happen to everyone. It's difficult to predict whether you will be affected or not.

You may have loose, or more frequent, bowel motions. This is because the radiotherapy irritates the lining of the bowel. Tell your doctor if you are troubled by these side effects. You might be able to take medicine to firm up your bowel motions and make them less frequent.

In rare cases, radiotherapy can cause constipation, with pain, sickness and bloating. Contact your doctor if you have these symptoms. Your doctor needs to check your bowel for a possible blockage.

Occasionally, radiotherapy to the pelvis can cause bleeding, which will show up in your bowel movements or urine, or from your vagina. This is usually caused by an increased growth of small blood vessels in that area after the treatment.

If you notice this, tell your doctor. Your doctor may call this problem telangiectasia (pronounced teel-an-gee-ek-tay-zee-a).

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