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Radiotherapy treatment

External radiotherapy uses high energy waves similar to x-rays to kill cancer cells. Read about when and how you have radiotherapy.

You can't feel external radiotherapy when you have it. But a course of radiotherapy usually has some side effects.

You have radiotherapy in a hospital radiotherapy department. Some hospitals have rooms near the hospital you can stay in if you have a long way to travel.

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

When you have it

You might have radiotherapy to: 

  • get rid of anal cancer - this is usually in combination with chemotherapy and is called chemoradiotherapy
  • relieve the symptoms of advanced anal cancer (such as pain) and control it for a period of time - this is called palliative radiotherapy


This is the main treatment for early stage anal cancer. Doctors know from research that this is a better treatment for anal cancer than surgery. If chemoradiotherapy is succesful, you won't need a permanent colostomy.

If you have radiotherapy with chemotherapy, you usually have treatment each weekday over 5 to 6 weeks. Each treatment lasts around 25 minutes.

Palliative radiotherapy

You generally have a short course of radiotherapy over a few days to control the symptoms of anal cancer. 

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.


Before each treatment session

The radiographers help you to get into the treatment couch. You may need to raise the arms over your head.

The radiographers line up the radiotherapy machine using the marks on your body. Once you are in the right position, they leave you in the room.

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

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: 
07 Jun 2016
  • Neoplasms of anal canal and perianal skin
    D. Leonard and others
    Clinical Colon Rectal Surgery. 2011 Mar;24(1):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. 25 (Supplement 3)

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