Side effects of radiotherapy for mouth and oropharyngeal cancer

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

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

In the video below, people affected by cancer who had radiotherapy discuss the general side effects of radiotherapy. It is 7 minutes and 51 seconds long.

Short term side effects

In the video below, people affected by cancer who had head and neck radiotherapy discuss the side effects of radiotherapy. It is 8 minutes and 26 seconds long.

Tiredness and  feeling weak

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 finished but it usually improves gradually. Some people can feel very tired and exhausted. 

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.

Feeling or being sick

You might feel sick at times. You can have anti sickness medicines. Let your treatment team know if you feel sick. 

Skin problems in the treatment area

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. Your radiographers will give you advice on washing the area and creams to soothe your skin. The soreness usually goes away within 2 to 4 weeks of ending the treatment. But your skin might always be slightly darker in that area.

During your radiotherapy treatment, the skin might break down around the treatment area. Your nurse will use special dressings to cover and protect the area. The area usually heals up over a couple of weeks.

Tell the radiotherapy staff if you notice any skin changes

Loss of appetite

You may lose your appetite because of radiotherapy. Having a sore, dry mouth can make eating difficult. You may also feel sick because of radiotherapy. This will make you feel less like eating.

Hair loss in the treatment area

Radiotherapy causes hair loss in the area of treatment. It may also cause hair loss where the radiation beam leaves the body (the exit site). 

It usually starts to grow back a few weeks after treatment. Ask your radiotherapy team to show you where you will lose your hair.

Mouth problems

Mouth problems caused by radiotherapy may include:

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.

Your mouth might get very dry, which can be uncomfortable. Radiotherapy can damage the glands that produce saliva. Saliva is important for taste, swallowing, and speech. 

Regular mouth care can prevent a dry mouth in some people. But sometimes problems can still happen. You can do several things to help with a dry mouth. Some of the following tips might help.

  • Sip drinks often to keep your mouth moist.
  • Suck on ice cubes, ice lollies or sugar free sweets.
  • Moisten your food with sauces, gravy, cream, custard or ice cream.
  • Chewing sugarless gum can make your salivary glands produce more saliva.
  • Use lip balm to keep your lips moisturised.
  • Use a soft toothbrush to clean your teeth and tongue, use moistened cotton wool if you can’t use a toothbrush for some reason.
  • Ask your doctor about gels or lozenges that stimulate saliva and artificial sprays.

Having a dry mouth can become a longterm side effect of radiotherapy. Speak to your doctor if this is a problem for you.

This can develop during treatment. Doing regular mouth care and using mouthwashes can help. Speak to your doctor or specialist nurse if you have bad breath.

Pain in the mouth and face 

It is common to have pain in the mouth or face during and after radiotherapy. Speak to your doctor or specialist nurse if you have pain. They can prescribe painkillers.

Difficulty swallowing

During and after treatment, you might have difficulty swallowing.

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.

You can have feeds through a nasogastric tube that goes up your nose and down into your stomach. Or you can have a PEG tube (percutaneous endoscopic gastrostomy tube) that goes through the skin into your stomach. Your nurse or dietician will tell you more about this if you need to have one. They will also show you and your relatives how to give the feeds. 

Difficulty opening your mouth

Radiotherapy can damage the nerve that controls the muscles that move our mouth. This problem is called trismus. Your doctor or nurse will give you exercises to help strengthen your muscles and to prevent this from becoming a long term problem.

Taste changes

Your food may taste different. Some people often describe having a metallic taste, but others may lose their taste completely. This usually gets better a few weeks after your treatment has finished.  

Tips:

Long term side effects

Swelling (lymphoedema)

After radiotherapy to treat a 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 are blocked, removed, or damaged.

Lymphoedema in the head or neck can also cause symptoms inside your mouth and throat. For example, swelling of your tongue and other parts of your mouth.

Tell your doctor or nurse straight away if you:

  • have any swelling in the head or neck area or a feeling of fullness or pressure
  • find it difficult to swallow
  • have changes in your voice

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

Unfortunately, it is not possible to cure lymphoedema. But things can be done to reduce the swelling and help you feel better. For example, positioning and lymphoedema exercises can help.

Hardening of underlying tissue

Radiotherapy can cause the underlying tissue to become firmer. This is also called fibrosis. Speak to your radiographer about what you can do to help prevent this from happening.

An increased chance of dental decay

Your saliva normally forms a protective film over your teeth. Having a permanently dry mouth increases the chance of tooth decay.  So, you need to take special care and do regular mouth care throughout the day.

Damage to the jawbone

Radiotherapy can sometimes damage the jawbone and break down the bone. This is because radiotherapy can reduce the blood supply to the bone. This is called osteoradionecrosis. This is rare but it can happen months or years after your treatment has finished. Symptoms include pain and swelling in your gums.

Before your radiotherapy, you usually see a specialist dentist. They can remove damaged or broken teeth and make sure your dentures fit properly. 

They will also show you how to keep your mouth and teeth clean. You will need to do this during your radiotherapy and for a few months afterward, or sometimes longer. 

Side effects if you have chemotherapy with radiotherapy

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

  • Head and Neck Cancer: United Kingdom National Multidisciplinary Guidelines, Sixth Edition
    J Homer and S Winter
    The Journal of Laryngology and Otology, 2024. Volume 138, Number S1

  • Early side effects of radiation treatment for head and neck cancer

    I Brook

    Cancer Radiotherapy, 2021. Volume 25, Issue 5, Pages: 507 to 513

  • Late side effects of radiation treatment for head and neck cancer

    I Brook

    Radiation Oncology Journal, 2020. Volume 38, Issue 2, Pages: 84 to 92

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact patientinformation@cancer.org.uk with details of the particular risk or cause you are interested in.

Last reviewed: 
04 Sep 2024
Next review due: 
04 Sep 2027

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