Side effects of external beam radiotherapy to the oesophagus

External beam radiotherapy directs radiotherapy beams at the cancer from a machine. This is different to internal radiotherapy. Internal radiotherapy means giving radiotherapy to the cancer from inside the body.

This page is about the side effects of external beam radiotherapy.

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

The side effects you have also depend on: 

  • how well you are before the radiotherapy 
  • the dose of radiotherapy 
  • how long you have it for 

Radiotherapy courses for advanced cancer are usually shorter and have less side effects.

Short term side effects

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

Tiredness and weakness

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 or months 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.


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 might also have pain or discomfort in your chest, particularly when you swallow.

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 you have any pain or discomfort.

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. You might be sick straight after swallowing (regurgitation).

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

Speech and language therapists play an important role during your treatment. They will help you with swallowing difficulties (dysphagia) and help you eat and drink safely. They can give information to your family or carer on how to support you with swallowing difficulties. A dietitian can also give advice on what to eat when you have swallowing problems.

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.
  • Avoid very hot drinks.
  • You can have high calorie drinks to boost your calorie intake if you need them.

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

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. You might not feel like eating. 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.


  • 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 might 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.

This is more likely to happen if your cancer is in the top part of your oesophagus, near to your voice box.

Reddening or darkening of your skin

Your skin might go red or darker in the treatment area. You might also get slight 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 feel sore. This may start after you have finished treatment. Your radiographers may give you creams to soothe your skin. The soreness usually goes away within 2 to 4 weeks of ending the treatment. 

The treatment area might look permanently tanned after your treatment has finished. This is not harmful. Later, you might appear to have very tiny broken veins in the skin called telangiectasia.

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. But some side effects can continue. Or you might notice some that begin months or years later.

There are things you can do to deal with any effects that you have. 

Breathing problems

A cough and breathlessness happen in some people who have radiotherapy to the chest area but this is not common. The problems are due to changes in the lung tissue called chronic radiation pneumonitis. They might start many months or a few years after treatment.

Let your doctor know if you notice any changes in your breathing or if you cough up a lot of mucus.

You might have regular tests to check how well your lungs work. Treatment with steroids or other medicines can help you to breathe more easily.

Narrowing of the food pipe

Rarely, your food pipe might become narrower and less stretchy over some months or years. This is called an oesophageal stricture. It can make it difficult for you to swallow.

If you develop a stricture, your doctor can stretch the food pipe slightly. They call this oesophageal dilatation. Stretching the food pipe opens it up again so that you can swallow food and drink more easily.

You have medicine to make you sleepy (sedation). Your doctor puts a tube called an endoscope down your throat. It has an area on it called a balloon. Your doctor expands the balloon to widen the food pipe. They repeat this a few times until the narrowing has gone. 

You might need to have this repeated if the narrowing happens again.

Side effects if you have chemotherapy with radiotherapy

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

  • Oesophageal cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    R Obermannova and others
    Annals of Oncology, 2022. Volume 33. Pages 992-1004

  • Cancer: Principles and Practice of Oncology (12th edition)
    VT DeVita, TS Lawrence, SA Rosenberg
    Wolters Kluwer, 2023

  • Overview of gastrointestinal toxicity of radiation therapy
    Accessed May 2023

Last reviewed: 
21 Sep 2023
Next review due: 
21 Sep 2026

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