External radiotherapy for thyroid cancer

Radiotherapy uses high energy X-rays to kill cancer cells. Look at the radiotherapy section in CancerHelp UK for more information about this treatment including

• What radiotherapy is
• How doctors plan your radiotherapy
• Possible radiotherapy side effects

External radiotherapy for thyroid cancer may be used

• As a first treatment for anaplastic thyroid cancer that cannot be removed with surgery
• To shrink any type of thyroid cancer that has come back after it was first treated
• As well as iodine-131 for papillary or follicular thyroid cancer that cannot be completely removed with surgery
• To treat thyroid cancer that has spread to another part of the body (secondary thyroid cancer)

Radiotherapy is not routinely used to treat medullary thyroid cancer. But it may be used for some people to control symptoms if the cancer cannot be completely removed, or has spread to other parts of the body.

You have external radiotherapy treatment in the hospital radiotherapy department. It is usually given as a course of treatments. You go to the hospital for treatment once a day, from Monday to Friday, with a break at the weekends for 4 to 6 weeks.

Radiotherapy is carefully planned. At your first visit you lie under a large machine called a simulator or a specially adapted CT scanner. The doctor uses the simulator or scanner to work out where to give your treatment. The treatment aims to kill the most cancer cells and miss as much healthy body tissue as possible. For radiotherapy to the thyroid area, you may have a clear plastic mask (mould) made before you start your course of radiotherapy. The mould fits over your face and neck. It attaches to the radiotherapy couch each time you are treated and helps to make sure that you don't move during your treatment.

The actual treatment takes a few minutes each day. The radiographer will help to position you on the couch and make sure that you are comfortable.

The staff will leave the room for the minute or two the machine is switched on. But they can hear you through an intercom, so you can call if you need them. The treatment doesn't hurt. You won't be able to feel it at all. You must lie very still for the few minutes it takes to treat you.

Having external radiotherapy does not make you radioactive. It is perfectly safe to be with other people, including children, throughout your treatment course.

Radiotherapy can cause tiredness and sore, red skin in the treatment area. Radiotherapy to the neck can also cause

• A sore throat
• Pain on swallowing
• A dry mouth
• A hoarse voice

There is more information about general radiotherapy side effects and side side effects of radiotherapy to the head and neck in the radiotherapy section.

Radiotherapy side effects usually start gradually during your course of treatment. Not everyone has side effects, but if you are going to get them, they will usually be at their worst at the end of your course. Over the following 2 to 3 weeks, they will slowly get better.

If you have side effects, do speak to the radiographer or nurse in your radiotherapy department. They will be able to help you. If your throat is very sore, you may need painkillers. Very rarely, where side effects are particularly severe, treatment can be stopped for a while to allow you to recover.

Remember not to put any lotions, powders or creams on skin in the treatment area without checking with your nurses, radiographers or doctors. If you have any soreness, these may make things worse not better. Ask at the radiotherapy department and the staff can give you something to soothe your skin if you need it.