Radiotherapy treatment

External radiotherapy uses high energy waves similar to x-rays to destroy cancer cells. 

You have radiotherapy in a hospital radiotherapy department. You go to the radiotherapy department from your ward if you’re already in hospital.

When do you have radiotherapy for anal cancer?

You might have radiotherapy:

  • combined with chemotherapy (chemoradiotherapy) 
  • to relieve symptoms of anal cancer that has spread (advanced anal cancer)


Chemotherapy combined with radiotherapy (chemoradiotherapy) is the main treatment for anal cancer that hasn't spread to other parts of the body.

Doctors know from research that this is a better treatment for anal cancer than surgery. If chemoradiotherapy is successful, you won't need a permanent colostomy.

For cancer that has spread

Radiotherapy can relieve the symptoms of advanced anal cancer, such as pain. It aims to shrink or control the growth of the cancer for a period of time. This is called palliative radiotherapy.

The radiotherapy room

Radiotherapy machines are very big and could make you feel nervous when you see them for the first time. The machine might be fixed in one position or able to rotate around your body to give treatment from different directions. The machine doesn't touch you at any point.

Before your first treatment, your therapy radiographers Open a glossary item will explain what you will 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 while you have treatment.

Photo of a linear accelerator

Before each treatment session

You might have to have a full bladder for radiotherapy to the anus. This means drinking a certain amount of water every day before your treatment. You then wait for your bladder to fill before you go into the radiotherapy room. Your radiographers let you know at your planning scan whether you'll be doing this. 

For some people having a full bladder for radiotherapy to the anus can help reduce the dose of radiation to normal healthy tissues. 

During the treatment

Your radiographers will help you to get onto the couch.

You'll be in the same position that you were in for your planning scan. This is usually lying face down with a special cushion underneath you. You might have to raise your arms over your head. 

You need to lie very still. The machine makes whirring and beeping sounds. You won’t feel anything when you have the treatment.

Your radiographers can see and hear you on a CCTV screen in the next room.

They will ask you to raise your hand if you need anything but it is important to stay as still as possible. 

You won't be radioactive

This type of radiotherapy won't make you radioactive. It's safe to be around other people, including pregnant women and children.

Travelling to radiotherapy appointments

You might have to travel a long way each day for your radiotherapy. This depends on where your nearest cancer centre is. This can make you very tired, especially if you have side effects from the treatment.

You can ask the therapy radiographers Open a glossary item for an appointment time to suit you. They will do their best, but some departments might be very busy. Some radiotherapy departments are open from 7am till 9pm.

Car parking can be difficult at hospitals. Ask the radiotherapy staff if you are able to get free parking or discounted parking. They may be able to give you tips on free places to park nearby.

The radiotherapy staff may be able to arrange transport if you have no other way to get to the hospital. Your radiotherapy doctor would have to agree. This is because it is only for people that would struggle using public transport and have no access to a car. 

Some people are able to claim back a refund for healthcare travel costs. This is based on the type of appointment and whether you claim certain benefits. Ask the radiotherapy staff for more information about this.

Some hospitals have their own drivers and local charities might offer hospital transport. So do ask if any help is available in your area.

Side effects of treatment

Side effects of radiotherapy for anal cancer can include feeling tired, sore skin around the anus and groin, or bladder irritation. You may also need to open your bowels frequently, or may feel sick.

Last reviewed: 
30 Apr 2019
  • Neoplasms of anal canal and perianal skin
    D. Leonard and others
    Clinical Colon Rectal Surgery, 2011. Volume 24, Pages 54-63

  • Anal cancer: ESMO-ESSO-ESTRO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    R. Glynne-Jones and others
    Annals of Oncology 2014. Volume 25, Pages iii10-iii20

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