Having radiotherapy treatment for anal cancer

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 you might have it

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.

You usually have radiotherapy for 5 days per week over 5 weeks.

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.

Type of radiotherapy

You have intensity-modulated radiotherapy (IMRT) for anal cancer. IMRT is a type of conformal radiotherapy. Conformal radiotherapy shapes the radiation beams to closely fit the area of cancer.

You can have IMRT on a standard radiotherapy machine, called a linear accelerator (LINAC).

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 it might 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 treatment

You usually get a bowel and bladder prep sheet a few weeks before your scan. This explains how you can help prepare your bladder and bowels for the planning scan and treatment. Following this advice can help reduce long term side effects to your bladder and bowels.

Your radiographer will explain how to prep your bladder and bowels. They will check you have emptied your bowels that day and ask you to empty your bladder. They will then explain how you can fill your bladder by drinking water. You will have to also do this before every treatment.

If your bladder is not full enough, or your bowels aren't empty enough, the scan may need to be repeated.

During the treatment

You need to lie very still. Your radiographers might take images (x-rays or scans) before your treatment to make sure that you're in the right position. 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 can talk to you over an intercom and might ask you to hold your breath or take shallow breaths at times. You can also talk to them through the intercom or raise your hand if you need to stop or if you're uncomfortable.

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 7 am till 9 pm.

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.

Hospital transport may be available if you have no other way to get to the hospital. But it might not always be at convenient times. It is usually for people who struggle to use public transport or have any other illnesses or disabilities. You might need to arrange hospital transport yourself.

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 and hospital transport.

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.

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