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.

Read more about the general side effects of radiotherapy

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:

Find out more information about mouth problems with cancer treatment and tips to help you cope

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.

Find out more about tube feeding and medicines for diet problems

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.

Tips for eating a soft diet

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.

Read about tips for putting on weight

It's important to maintain your weight during 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

Find out more about managing diet problems in cancer

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.

Find out about tube feeding

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​ 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

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

Go to the Lymphoedema Support Network website

The British Lymphology Society has a directory of lymphoedema services.

Go to the British Lymphology Society website

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. 

Find out more about lymphoedema and cancer

An underactive thyroid (hypothyroidism)

If your thyroid gland is in the radiotherapy treatment area, you may develop an underactive thyroid. This is called hypothyroidism. It can develop a few months or years after treatment.

Common symptoms of hypothyroidism include:

• tiredness

• weight gain

• feeling cold

• constipation

• joint or muscle pain

• poor memory   

If left untreated it can cause heart problems.

You have regular blood tests to check your thyroid hormone levels after treatment.

If you develop hypothyroidism, you take medicine to replace the thyroid hormone. This is usually a tablet you take every day. This normally improves your symptoms but it can take several months.

Worries about treatment side effects

You may feel anxious about radiotherapy side effects and this is normal. It can help to talk through any worries you have with your doctor, nurse or radiographer.

Coping with cancer