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:

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 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

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.

Voice over: When having radiotherapy to your head and neck, you can experience many different side effects. One of these might be weight loss.

Louise: Unfortunately, weight loss with head and neck radiotherapy is very common. Obviously we don't want you to lose too much weight, so we would work very closely with the dietitian to support you.

Charlie: The clinical team in advance warned me I would lose weight. They told me to prepare for it. They told me to eat lots of calories in advance and I thought they were kidding, but the reality is, the weight did drop very, very quickly.

Louise: Initially, if you start to notice any problems eating, we would recommend you start to move to a slightly softer diet. Foods that are soft, easy to swallow, but highly nutritious.

Charlie: Soups and gravies and maybe move on to scrambled eggs and rice puddings.

Louise: If you then find that that starts to become problematic, we do have some special little drinks that you can use as a meal replacement.

Tasha: I had a smoothie drink that was given to me by the doctors. It's like a smoothie with calories in and it's a small bottle so you're just topping up what you’re missing not eating and drinking fully.

Charlie: My swallow mechanism just stopped working, so everything I had to take was being taken through the stomach tube.

Louise: Occasionally the radiotherapy can have a real impact on how easily you can swallow and if it starts to become very problematic, they may suggest they use feeding tubes to help ensure you are getting the right nutrients.

Voice over: For information on other head and neck radiotherapy side effects, visit the Cancer Research UK website.

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.

Voice over: When having radiotherapy to your head and neck, you can experience many different side effects. One of these might be changes to your voice.

Charlie: They found cancer in my voice box so that was part of the treatment area. As the weeks progressed in treatment, I started losing it.

Louise: If you're having radiotherapy to your larynx, your voice box, you may well find that you end up with an altered voice. This can happen during treatment and we can't always guarantee your voice will be the same as it was after treatment.

Charlie: I lost it in total probably for maybe 2 weeks, so my wife had a peaceful couple of weeks for that period of time, and it just came back. But it was quite fragile. So I learned to take it easy, and even now, 18-20 months after treatment, I can feel it if I talk too much.

Louise: We would recommend you rest your voice as much as possible and if needed, carry a pen and paper around with you, so you can continue to communicate.

Voice over: For information on other head and neck radiotherapy side effects visit, the Cancer Research UK website.

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. 

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.

You can talk to the Cancer Research UK nurses for general information and support on freephone 0808 800 4040, from 9am to 5pm, Monday to Friday.

Last reviewed: 
21 Feb 2024
Next review due: 
21 Feb 2027

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