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External radiotherapy

For external radiotherapy, a machine aims a precisely targeted dose of radiation to the cancer. Find out what happens. 

External radiotherapy uses high energy rays similar to x-rays to kill cancer cells. You usually have a type of radiotherapy called intensity modulated radiotherapy (IMRT) for mouth or oropharyngeal cancer. 

You have your treatment in the hospital radiotherapy department. You usually have it Monday to Friday. And have a break at the weekend. The treatment can be over 4 to 7 weeks. This depends on the:

  • size of your cancer
  • type of cancer
  • hospital treating you

You need to travel to the hospital each time you have treatment. Some hospitals have rooms nearby where you can stay in if you have a long way to travel.

You go to the radiotherapy department from your ward if you are staying in hospital.

When you have it

You may have external radiotherapy:

  • on its own
  • after surgery
  • with chemotherapy
  • to control symptoms

Radiotherapy after surgery is called adjuvant therapy. It helps to stop your cancer coming back. You may have it because:

  • your tumour was difficult to remove
  • your surgeon thinks there may be cancer cells left behind
  • the tumour had spread locally into nearby structures
  • your doctor found cancer cells in your lymph nodes

You might have radiotherapy and chemotherapy together if your cancer has spread beyond where it first started. This is called chemoradiotherapy. Rarely, you might have chemoradiotherapy for very small mouth cancers.

Radiotherapy can help relieve symptoms in advanced cancer. You may hear this called palliative radiotherapy. The treatment relieves symptoms by shrinking the cancer. 

Internal radiotherapy (brachytherapy)

Sometimes mouth and oropharyngeal cancer is treated with internal radiotherapy (brachytherapy).

The radiotherapy room

Radiotherapy machines are very big and can be daunting at first. Some are fixed in one position, but others rotate around your body.  

Before you start treatment your radiographers explain what you'll see and hear. In some departments the treatment rooms have docks for you to plug in music players. So you can listen to your own music.

Photo of a linear accelerator

During the treatment

You need to lie very still. The machine makes whirring and beeping sounds. You can't feel the radiotherapy when you have the treatment. 

Your radiographers watch and listen to you on a CCTV screen in the next room. They might ask you to hold your breath or take shallow breaths at times. Tell them if you need to move or want the machine to stop.

You won't be radioactive

External radiotherapy doesn't make you radioactive. It's safe to be with other people throughout your course of treatment.

Travelling to radiotherapy appointments

Tell the radiotherapy department staff if you prefer treatment at a particular time of day. They can try to arrange this.

Radiotherapy can make you tired, especially if you have a long journey. You could ask a family member or friend to drive you to the hospital a couple of times a week. 

Car parking can be difficult at hospitals. It’s worth asking the radiotherapy unit staff:

  • if they can give you a hospital parking permit
  • about discounted parking rates
  • where you can get help with travel fares
  • for tips on free places to park nearby

The radiotherapy staff can usually help to arrange transport for you if you need it. Some hospitals have their own drivers or can arrange ambulances. Some charities offer hospital transport.

Side effects of treatment

Radiotherapy for mouth or oropharyngeal cancer can give you:

  • red or sore skin around the area 
  • dry and sore mouth 
  • taste and smell changes 
  • voice changes 
  • nausea (feeling sick) 
Last reviewed: 
30 Sep 2014
  • Head and Neck Cancer: Multidisciplinary Management Guidelines (4th Edition)

    British Association of Head and Neck Oncologists, 2011

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