Radiotherapy for head and neck cancer

Radiotherapy uses high-energy rays to destroy the head and neck cancer cells, while causing as little damage as possible to healthy tissue. Radiotherapy can be used on its own if the cancer is small.

If the cancer is larger, radiotherapy is often given with other treatments. It may be used:

  • after surgery, with or without chemotherapy
  • in combination with chemotherapy (called chemoradiation), without surgery
  • in combination with the targeted therapy drug cetuximab.

Treatment for head and neck cancers is usually with external beam radiotherapy. You will have treatment in a hospital radiotherapy department, usually as a series of short daily sessions from Monday to Friday. Treatment may take four to seven weeks, depending on your situation.

Some people may have internal radiotherapy. This is where a radioactive substance is placed into the tumour for a few days.

Your radiotherapy doctor (clinical oncologist) or specialist nurse will tell you more about your treatment and what to expect.


Radiotherapy treats cancer by using high-energy rays to destroy the cancer cells, while doing as little harm as possible to normal cells. It’s an important treatment for head and neck cancers. Radiotherapy can be used on its own but is often given in combination with chemotherapy (called chemoradiation).

Radiotherapy for early-stage cancers

Radiotherapy can be used on its own to treat cancers that are small and haven’t spread (early-stage). It’s often used for cancers in harder-to-reach areas, such as the back of the mouth or throat. Radiotherapy may also be used when surgery could seriously affect important functions such as speech and swallowing.

Radiotherapy for locally advanced cancers

If a cancer is larger, or is affecting other tissues nearby (locally advanced cancer), radiotherapy is usually combined with other treatments. Radiotherapy may be given:

  • after surgery (with or without chemotherapy) to destroy any remaining cancer and reduce the risk of cancer coming back
  • in combination with chemotherapy (chemoradiation), without surgery
  • in combination with the targeted therapy drug cetuximab
  • to reduce symptoms (palliative radiotherapy).

Radiotherapy after surgery (adjuvant radiotherapy)

If you have surgery for advanced cancer, you’ll usually be given radiotherapy afterwards. This is to reduce the risk of the cancer coming back and is called adjuvant radiotherapy. Sometimes both chemotherapy and radiotherapy are given together after surgery. This called adjuvant chemoradiation.

If you need adjuvant treatment, your specialist team will decide whether radiotherapy or chemoradiation is best for your situation.


Chemoradiation is often the main treatment for advanced head and neck cancers. It may be used:

  • to treat cancers that can’t be removed with an operation
  • to treat cancers in harder-to-reach areas such as the nasopharynx or throat
  • when surgery could cause unacceptable changes to speech or swallowing.

Radiotherapy and cetuximab

Combining chemotherapy and radiotherapy (chemoradiation) is a very effective treatment for head and neck cancer but it can also cause severe side effects. Some people can’t have chemoradiation because they aren’t well enough to cope with these side effects or they have other health problems that make chemotherapy too risky. Instead, they may be given radiotherapy in combination with a targeted therapy drug called cetuximab.

Palliative radiotherapy

Sometimes it’s not possible to cure a cancer, and the main aim of treatment is to relieve symptoms. This is called palliative treatment.

Palliative radiotherapy may be used to:

  • stop bleeding from a tumour
  • shrink a tumour that is causing swallowing or breathing difficulties
  • relieve symptoms if the cancer has spread to other parts of the body, such as the lungs or bones.

How radiotherapy is given

Radiotherapy can be given in two ways:

  • From outside the body as external-beam radiotherapy. A beam of x-rays is directed at the cancer from a large machine called a linear accelerator. This is the most common way of giving radiotherapy to the head and neck area.
  • By putting a radioactive source into the tumour and leaving it there for a few days. This is known as internal radiotherapy, interstitial radiotherapy or brachytherapy.

External-beam radiotherapy

Treatment is given in the hospital radiotherapy department.

It can be planned in different ways. It may be given:

  • Monday–Friday, with a rest at the weekend (this is the most common method)
  • more than once a day
  • every day including at the weekend.

Treatment may take 4−7 weeks, depending on the type and size of the cancer. Your radiotherapy doctor (clinical oncologist) or specialist nurse will discuss the treatment with you.

Conformal radiotherapy (CRT) is the most common type of external-beam radiotherapy used for head and neck cancers.

A special attachment to the radiotherapy machine arranges the radiation beams to match the shape of the cancer. Shaping the radiotherapy beams reduces the radiation given to surrounding healthy cells.

Intensity-modulated radiotherapy (IMRT) is available in some hospitals. This way of giving radiotherapy shapes the beams even more accurately to the exact shape of the cancer. IMRT allows the doctors to give higher doses of treatment to the cancer and lower doses to the surrounding healthy tissue.

Research has found that, for some people, having IMRT rather than standard radiotherapy may reduce some long-term side effects such as a dry mouth.

We have more detailed information about external-beam radiotherapy.

Internal radiotherapy

This involves putting a radioactive source directly into the cancer. Over a few days, this gives a high dose of radiotherapy into the tumour.

It’s sometimes used:

  • to treat small tumours in the mouth or lip
  • with external-beam radiotherapy to give an additional dose of radiotherapy or ‘boost’ into the tumour.

For this treatment, you will need to stay in a single room in hospital for a few days, until the doctor removes the radioactive source from your body. During this time, visitors will be restricted. It will be safe for your family and close friends to visit you for short periods. However, children and pregnant women won’t be allowed to visit. This is so they’re not exposed to even tiny amounts of radiation.

The doctors and nurses caring for you will also only be able to stay in your room for short periods of time.

Once the radioactive source is removed, the radioactivity disappears and it’s perfectly safe to be with other people.

The radioactive source causes some swelling in the tissues nearby. This swelling usually settles by the time the source is removed (generally about seven days later). The soreness may last for up to about six weeks.

We have more detailed information about internal radiotherapy.

Back to About radiotherapy

Possible side effects

You can get side effects during radiotherapy treatment to your head and neck – these usually improve a few weeks after treatment is over.

Who might I meet?

You will meet many different specialists before, during and after radiotherapy treatment.