External radiotherapy for mouth cancer

For external radiotherapy a machine directs a high dose of radiation to the area of the tumour. You have the treatment in the hospital radiotherapy department. You go to the hospital for treatment once a day, from Monday to Friday, with a break at the weekends. The length of the course of treatment varies, depending on the type and size of the cancer and the aim of the treatment. But it is usually for between 4 to 7 weeks.

Your doctor will make sure that the whole area with cancer is treated, as well as 1 to 2 centimetres around it. This is to make sure the radiation doesn't miss any stray cancer cells. Doctors call these stray cells microscopic spread. A scan can't pick up these cells because they are so small. But if they are left, they could grow and your cancer could come back.

You may feel frightened about having radiotherapy or nervous of the big machines in the department. A visit to the radiotherapy department before you start your treatment can help to reduce anxiety. The radiographer or nurse can reassure you by explaining more about what to expect and answering any questions you have.

IMRT is a newer form of radiotherapy where both the radiation beam and the dose within the beam are shaped to match the tumour. This type of radiotherapy treatment is still quite new, but should now be available in every cancer network in England.

Radiotherapy where just the beam is shaped is called conformal radiotherapy – the beam conforms to the shape of the cancer. IMRT is a step on from that, as the radiation dose is also changed within the shaped beam, depending on the thickness of the tumour.

With any type of conformal radiotherapy, there is less normal tissue in the way of the radiotherapy beam. So you may have fewer severe side effects such as a dry mouth and sore throat. There is a small risk that the shaped radiotherapy will miss some of the cancer and so may not work so well. Research results show that IMRT for head and neck cancers causes less severe long term side effects than conventional radiotherapy. For example, a dry mouth is less severe when doctors are able to lower the radiation dose that the salivary glands receive.

If you have radiotherapy to any area of your face and neck, you usually need to wear a treatment mask, also called a cast, mould or shell. The mask keeps your head and neck very still during your treatment. Keeping your head very still helps to make sure that the radiation only goes to the exact treatment area. The mask fits over all or part of your face and neck. The radiographer attaches it to the radiotherapy couch each time you have treatment.

You have your mask made during your first planning appointment. Before you have anything done, the staff will explain what is going to happen. The mould room technician makes your mask individually for you in the mould room. It should feel comfortable and secure when you wear it. Having the mask made won't hurt. But it may feel a bit strange to have someone working so near to your face. You may have an impression of your teeth made with gel. The technician will put the gel into your mouth and take an imprint of your teeth. This takes between 5 and 10 minutes. The technician will also make an impression of your lower jaw and neck. The whole visit takes about 30 minutes.

Masks are made from either a thin sheet of clear plastic or various materials which mould into shape easily when they are heated up. The technician will cut holes in the mask for your nose and mouth so that you can breathe comfortably. Below is a picture of a mask.

Radiotherapy treatment is carefully planned. During your planning appointment, you may have a CT scan or may lie under a large machine called a simulator. This is so the tumour can be seen from all sides (3 dimensionally or 3D). The picture below shows a simulator.

Using information from the CT scan or simulator your treatment team work out exactly where to give the treatment, in order to

• Hit all of the tumour and a border of tissue around it, where there are most likely to be cancer cells
• Avoid as much of the surrounding healthy body tissue as possible

Each treatment only takes a few minutes. The radiographer will help position you on the couch and make sure your mask feels comfortable. You will be left alone for the minute or two the machine is switched on. The staff will be able to hear and see you through a CCTV link, so you can call if you need them.

The treatment itself doesn't hurt – you won't be able to feel it at all. Having external radiotherapy does not make you radioactive. It is perfectly safe to be with other people, including children, throughout your treatment course.

In the main radiotherapy section you can find detailed information about

• What radiotherapy involves
• How your radiotherapy treatment is planned