Head and neck radiotherapy side effects

The main side effects from radiotherapy to the head and neck include:

  • mouth problems
  • problems with your teeth
  • weight loss
  • difficulty swallowing
  • changes to your voice
  • swelling in your neck and face (lymphoedema)

You may also experience more general side effects of radiotherapy such as hair loss, sore skin and tiredness.

Like all side effects of radiotherapy, you might not feel these straight away. Side effects tend to come on gradually as you go through your treatment. And for a few weeks afterwards. Everyone reacts differently to radiotherapy, so how you feel varies from person to person. 

Problems with your mouth and teeth

During radiotherapy you may have problems with your mouth and teeth. These can include:

The cells lining your mouth are sensitive to radiation. Radiotherapy is likely to make your mouth sore and you might have ulcers after a week or so. This is called oral mucositis.

The soreness usually only lasts while you are having treatment and for a few weeks afterwards. Your radiotherapy team can give you painkillers to help. Following a mouthwash routine from the start of radiotherapy will also help.

You might need to have a feeding tube into your stomach if your mouth is sore and stopping you from eating or drinking properly.

Smoking and alcohol can make the soreness worse. You can try to cut down on smoking. Talk to your radiotherapy team about nicotine replacement treatments to help with this. 

This video shows people affected by cancer, talking about having a sore mouth as a side effect from radiotherapy for head and neck cancer. The video is around 2 minutes long.

Your treatment might affect the salivary glands so that they produce less or no saliva. It can be uncomfortable to chew or swallow. Let your radiographer or doctor know if you're having problems.

After the treatment ends it can take some time for saliva production to get back to normal. If the radiotherapy treatment area includes the salivary glands, you might have a permanently dry mouth afterwards. Your doctor will talk to you about this before you start treatment.

Some of the following tips might help:

  • Ask your doctor to prescribe medicines that stimulate saliva.
  • Sip drinks often to keep your mouth moist.
  • Moisten your food with sauces, gravy, cream, custard or ice cream.
  • Chewing sugarless gum can make your salivary glands produce more saliva.
  • Clean your tongue with a liquid made from a teaspoonful of bicarbonate of soda in a litre of warm water.
  • Use lip balm to keep your lips moisturised.
  • Use moistened cotton wool or a soft toothbrush to clean your tongue.
  • Ask your doctor to prescribe artificial saliva sprays or gels.

This video shows people affected by cancer, talking about having a dry mouth as a side effect from radiotherapy for head and neck cancer. The video is around 1 minute long.

Radiotherapy can make it easier for infections of the mouth to develop, such as thrush. The radiotherapy team will check your mouth regularly during your treatment.

Let your doctor or nurse know if you have any white patches on the inside of your mouth or on your tongue. They can prescribe medicines to help.

Radiotherapy can affect your taste buds. You might notice changes in the way your food tastes. Some people say their food has a metallic taste. Others say that all foods taste the same.

The radiotherapy team can arrange for you to talk to a hospital dietitian for advice about overcoming taste changes.

There are ways to help make food tastier. But you might need to wait to try these until your mouth has recovered from the treatment and is not sore any more.

This video shows people affected by cancer, talking about having changes to their taste as a side effect from radiotherapy for head and neck cancer. The video is around 1 and a half minutes long.

You visit a dentist before you start radiotherapy to the head and neck. They look for any teeth that might be decaying or already decayed and will remove them. This is because radiotherapy makes it more likely that your teeth will decay so it's best to take them out first to avoid problems. Your mouth will also not heal as quickly after radiotherapy.

You'll also need to go for check ups at the dentist more often. Fluoride treatment might help to protect your teeth. You can have this as a mouthwash to use twice a day.

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

This video shows people affected by cancer, talking about changes to their teeth as a side effect from radiotherapy for head and neck cancer. The video is around 1 and a half minutes long.

Difficulty swallowing

Radiotherapy for cancer in the head or neck area can cause swelling and soreness in the throat. Your throat might be very sore, and you may find it difficult to swallow solid food (dysphagia). You might need to have strong painkillers if your throat is too sore to swallow food. Or have a feeding tube fitted.

Whether you have problems swallowing depends on which part of the head or neck you are having treatment to. It also depends on the dose of treatment. Difficulty swallowing may be worse and can last longer if you have chemotherapy at the same time as radiotherapy.

You may see a Speech and Language Therapist (SLT) before you start treatment if this is likely to affect your swallowing. An SLT can assess your swallowing during and after treatment. They can teach exercises to support you with swallowing difficulties. And they work with a dietitian if you are finding it difficult to eat.

Talk to your healthcare team if you have any problems swallowing.

Weight loss

Radiotherapy to your head and neck area can make you lose weight. This can be because you have mouth problems such as a sore or dry mouth, which can make swallowing difficult. You may also have a poor appetite.

These effects might be temporary and gradually go back to normal after treatment ends. But for some people, the effects may be permanent. There are things you can do to help keep your weight up.

It's important to maintain your weight for radiotherapy treatment. Your radiotherapy is planned very precisely using your body measurements. This means if you lose or gain weight during radiotherapy it can change the amount of radiation that the cancer or nearby healthy cells receive. Losing too much weight might also make you feel weaker.

During your radiotherapy treatment:

  • you might see a dietitian once a week who can help to advise you on foods that are easier to eat
  • your doctor or dietitian may give you nutritional supplements, such as high calorie drinks to help keep your weight up
  • your doctor might prescribe strong painkillers if your throat is very sore and you have pain when swallowing
  • try not to drink alcohol (especially spirits) or smoke because this can make your mouth and throat very sore

If eating becomes very difficult you might have a feeding tube put into your stomach through your skin. Or a liquid feed through a drip. Some hospitals might arrange for you to have a feeding tube before you start radiotherapy. This is to stop you from losing too much weight. This varies from hospital to hospital.

This video shows people affected by cancer, talking about weight loss as a side effect from radiotherapy for head and neck cancer. The video is around 2 minutes long.

Changes to your voice

Your voice might get hoarse if you have radiotherapy to your voice box to treat cancer of the larynx. It could disappear completely for a while during and after the treatment. Your voice should come back within a few weeks but may never sound quite the same as it was.

Radiotherapy for other types of head and neck cancer might make your voice change a little during and for a few weeks after the treatment. Your voice should go back to normal once your treatment ends.

You might find it useful to carry a small notebook and pen so that you can always write notes to people if you need to.

Laptop computers or electronic notebooks are other ways you can communicate. Various types of small portable machines are available. Your speech and language therapist can advise you on which may suit you best.

This video shows people affected by cancer, talking about having changes to their voice as a side effect from radiotherapy for head and neck cancer. The video is around 4 minutes long.

Swelling in the neck and face (lymphoedema)

After radiotherapy for head and neck cancer, you are at risk of getting swelling called lymphoedema in your neck or face. Lymphoedema is pronounced lim-fo-dee-ma. 

Lymph fluid is in all body tissues. It comes from the tiny blood vessels into the body tissues. Usually, it drains back into the bloodstream through channels called lymph vessels. These are part of the lymphatic system.

A build up of lymph fluid in an area of the body can happen if lymph drainage channels or lymph nodes Open a glossary item are blocked, removed or damaged. This causes swelling.

Radiotherapy can cause changes in the lymphatic system in the head and neck area. It's a long-term (chronic) condition. It can’t be cured, but it can usually be well controlled. 

Sometimes the cancer itself can affect your lymphatic system and cause lymphoedema.

Symptoms can include:

  • swelling of your tongue and other parts of your mouth
  • swelling or a feeling of fullness or pressure
  • difficulty swallowing
  • changes to your voice

Symptoms may develop soon after treatment. Or it can take many months or a few years to appear after radiotherapy.

What to do if you have symptoms

Contact your doctor or specialist nurse if you know you’re at risk of lymphoedema and you have any of the symptoms above. Early treatment can help to control swelling and stop it getting worse. Your doctor or nurse can refer you to a lymphoedema specialist.

The Lymphoedema Support Network can tell you how to get lymphoedema care within the NHS.

The British Lymphology Society has a directory of lymphoedema services.

Lymphoedema is easier to control if treated early. It is important that you are referred to a lymphoedema specialist if you have signs of swelling. This is usually a nurse or physiotherapist. 

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  • Devita, Hellman and Rosenberg's Cancer: Principles and Practice of Oncology (12th edition)
    VT Devita, TS Lawrence and SA Rosenberg
    Wolters Kluwer Health, 2023

  • Dysphagia management in head and neck cancers
    K Thankappan and others, 
    Springer Nature, 2018

  • Cancer and its Management (7th edition)
    J Tobias and D Hochhauser
    Wiley Blackwell, 2015

  • Head and Neck Cancer: Treatment, Rehabilitation, and Outcomes (2nd edition)
    E Ward and others, 
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Last reviewed: 
21 Feb 2024
Next review due: 
21 Feb 2027

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