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Side effects of radiotherapy

Find out about the side effects of 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:

Tiredness and weakness

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 might need to sleep after each radiotherapy session. 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: for example, exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.

Sore mouth and throat

Your mouth and throat might get sore. It may be painful to swallow drinks or food. You will have mouth washes to keep your mouth healthy.

You can have painkillers to reduce the soreness. Take them half an hour before meals to make eating easier.

Tell your doctor or nurse if your throat is sore.

Difficulty swallowing

During and after treatment, you might have a feeling of a lump in the throat when you swallow. This can make it difficult to swallow solid foods.

This problem is often at its worst about 10 days to 2 weeks after you finish treatment.

Ask to see a dietitian if you have problems with eating and drinking
Tips for eating and drinking
  • Drink about 3 litres of water a day while having treatment.
  • Eat soft foods.
  • Eat slowly and avoid eating late in the day.
  • Drink plenty during and after meals to soften your food.
  • Eat small amounts often rather than big meals.
  • Try different foods to find out which are easiest to swallow.
  • You can have high calorie drinks to boost your calorie intake if you need them.

You might need to have liquid food into your vein or through a tube into your nose or stomach if you can’t eat enough.

Feeling or being sick

Feeling or being sick can be severe. It can start a few hours after treatment and last for a few days. Anti sickness injections and tablets can control it. Tell your doctor or nurse if you feel sick. You may need to try different anti sickness medicines to find one that works.

Contact your doctor or nurse straight away if you’ve been sick more than once in a day.

Tips

  • Avoid eating or preparing food when you feel sick.
  • Avoid fried foods, fatty foods or foods with a strong smell.
  • Drink plenty of liquid to stop you from getting dehydrated.
  • Relaxation techniques help control sickness for some people.
  • Ginger can help – try it as crystallised stem ginger, ginger tea or ginger ale.
  • Fizzy drinks help some people when they are feeling sick.

Loss of neck and chest hair

Your hair may fall out in the treatment area.

Voice changes

Your voice might get husky or croaky and sound weaker. This can last for a while after your treatment.

Problems with your teeth

You might be more likely to get mouth infections and tooth problems. You may need dental checkups more often. Fluoride mouthwashes twice a day can help to protect your teeth.

Remember to tell your dentist you have had radiotherapy to your mouth before you have any dental work. They may need to change your treatment.  They might also need to talk to your radiotherapy doctor before giving you any treatment.

Reddening or darkening of your skin

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. However your skin may be slighter darker in that area permanently.

Tell the radiotherapy staff if you notice any skin changes.

Long term side effects

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

Side effects if you have chemotherapy with radiotherapy

Chemotherapy combined with radiotherapy can make some side effects worse. Combining these treatments is called chemoradiotherapy.

Information and help

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