Radiotherapy uses high energy beams of radiation to destroy cancer cells. Radiation is essentially a way that energy or heat moves around. A nice example is sunshine! Being treated with invisible rays sounds pretty sci-fi but the reality is it’s a very effective treatment designed to kill cancer cells, while causing as little harm as possible to your normal cells. 

When would I need radiotherapy?

Not everyone with cancer needs radiotherapy. It depends on the type you have and where it is in your body.

You might have radiotherapy along with other cancer treatments like chemotherapy. It’s also sometimes given before surgery to shrink a tumour before it’s removed

There are two types of radiotherapy: external and internal radiotherapy. If you need to have radiotherapy, a member of your care team will explain which one you’ll need, and how you can prepare for it.

More about external radiotherapy

This type of radiotherapy is probably the one that comes to mind. You’ll lie down while a large machine aims high-energy rays at the affected area of your body. It’s called 'external' because it’s done from outside the body. 

Is it painful?

Having external radiotherapy is a bit like having an X-ray. It’s not painful and only lasts a few minutes. It’ll probably feel a bit weird and daunting the first time you have it but you’ll get used to all the high tech equipment and big machinery. 

Who can I talk to about my questions?

The machine is operated by someone called a radiographer – they should be able to set your mind at ease by explaining what you’ll see and hear, and answer any of your questions. You might be able to listen to music or a podcast while you’re having it. It’s important that you feel confident about the treatment so if you have any doubts or anxieties, make sure you tell someone before it starts.

What will actually happen?

The radiographer will operate the machine from outside the room but will be watching you through a window or camera. You’ll be able to speak to each other through an intercom. You might be asked to expose the part of your body where you need the treatment. This could mean taking some items of clothing off, or wearing a gown. The team of technicians should treat you very respectfully and if you have any worries about this, make sure you ask beforehand. 

It can be a bit uncomfortable but it’s important to stay as still as you can. You might need to wear a plastic mould or mask over the part of your body that’s being treated to stop it moving. This will be made before treatment starts – it’s a bit weird at first, but you won’t have to have it on for long. You might also be asked if a small permanent mark can be made on your skin to make sure that the radiotherapy can be given accurately – they’ll look like freckles and will let you wash as normal. If you aren’t happy with this, let someone know and there might be alternatives.  

How long will it last?

The treatment is really quick – you should be in and out in 10-15 minutes. Most time is spent setting up the machine and getting you ready.

A course of external radiotherapy can last between one day and seven weeks. It’s usually given Monday to Friday, with breaks at the weekends and bank holidays.

More about internal radiotherapy

Internal radiotherapy is when radiation is placed inside your body using a drink or tablet, an injection into your vein, or wires or implants which stay inside your body.

The cancer cells absorb the radioactive material more than normal cells. So the cancer cells receive a higher dose of radiation, causing them to die. This might sound unnerving but we’re talking about good radiation and it is all perfectly safe. 

If you have this type of radiotherapy, you’ll stay in hospital until the radiation has left your body and you might need to be kept away from other people. This can feel isolating so it’s important to talk to your care team, or someone else, about how you’re feeling. How long you are in hospital for will depend on your treatment. It could be just a few hours or a few days.

If you google internal radiotherapy, you might get information about internal radiotherapy being used for vaginal cancer. This type of cancer is extremely rare in young people so we’re talking about other cancer types here. If you do have vaginal cancer though, the best thing you can do is speak to your consultant or someone in the team looking after you for advice and support. 

Read about the side effects of radiotherapy.

Updated March 2018, next review due 2021.