Radiotherapy
Your health expert: Dr Sunil Skaria, Clinical Oncologist
Content editor review by Victoria Goldman, April 2023
Next review due March 2026
Radiotherapy is a treatment for cancer. It uses high doses of radiation to kill cancer cells. Over half of people who are treated for cancer have radiotherapy. Radiotherapy is often used with other treatments, such as chemotherapy and surgery.
About radiotherapy
In radiotherapy, high-energy radiation is targeted at the area of your body affected by cancer. The aim of radiotherapy is to target and destroy the cancer cells without damaging your healthy cells as much as possible.
You may have radiotherapy:
- to cure some types of cancer
- on its own or with chemotherapy
- before surgery to make the tumour (growth of cells) easier to operate on
- after surgery to destroy any remaining cancer cells
- to help control your symptoms and improve your quality of life if your cancer can’t be cured
Types of radiotherapy
There are several different types of radiotherapy procedure.
- External beam radiotherapy is the most common type of radiotherapy. Radiation is directed into the affected area of your body from outside your body. This usually uses a machine called a linear accelerator (linac).
- Internal radiotherapy (brachytherapy) is when radiation is delivered from inside your body. This involves placing radioactive implants near to or inside the affected area of your body.
- Radioisotope therapy involves treatment with radioactive medicines. You’re given these medicines as an injection or as a drink or capsule to swallow. The medicines target cancer cells in your body.
Which type of treatment you have depends on the type of cancer you have, and which part of your body is affected. Your radiotherapy will be designed for your particular circumstances and tailored to you. The following information looks at external beam radiotherapy and internal radiotherapy (brachytherapy) in more detail.
Preparing for radiotherapy
If your doctor recommends you have radiotherapy, they’ll discuss this with you and check you’re happy to go ahead. If you are, you’ll be referred to your nearest radiotherapy department. Not all hospitals have a radiotherapy department, so you may need to go to a specialist cancer hospital or a large regional hospital. You’ll usually start by seeing a radiation oncologist – a specialist cancer doctor who’ll plan and oversee your treatment.
External beam radiotherapy
If you're having external radiotherapy, you may be asked to come to the radiotherapy department for a CT planning scan. This will help to plan your treatment. It is sometimes called ‘simulation’.
You may be given special instructions about things you need to do before your planning scan, such as:
- having an enema to clear your bowel
- needing your bladder to be full or empty
Your radiotherapy team will want to take scans in exactly the same position that you’ll be in when you have your radiotherapy treatment. During the planning scan, they may:
- use cushions and other equipment to support you
- tattoo tiny dots on your skin to show you’re in the right position for your treatment
- fit you with a special plastic mask if you’re going to have radiotherapy to your head or neck
It may take up to a couple of weeks to plan treatment with external beam radiotherapy after having your scan.
Your doctor may also take X-rays or CT scans at the start of each of your radiotherapy sessions. This is called image-guided radiotherapy. You may need to have these scans with some types of cancer, such as lung cancer – when the area being targeted with the radiotherapy moves every time you breathe. Image-guided radiotherapy helps your doctor:
- make sure you’re in the best position for your treatment
- target the right area more accurately, giving better results and fewer side-effects
Sometimes, your doctor may implant little metal markers (‘seeds’) before you begin your radiotherapy. This can help to show up the target area on an X-ray during treatment.
Internal radiotherapy (brachytherapy)
If you’re having internal radiotherapy (brachytherapy), you’ll be asked to have a scan beforehand. This is so your doctor can work out:
- how much radiation you need
- where to put the implants
With internal radiotherapy, you can sometimes have the treatment on the same day as your scan.
What happens during radiotherapy?
External beam radiotherapy
You usually have external beam radiotherapy in small amounts (called fractions) over a number of days or weeks. This is usually on weekdays, so you should get weekends off. You’re most likely to have treatment as an outpatient, rather than staying in hospital. The whole session usually takes less than 30 minutes. This includes the time it takes to get you in the right position.
You’ll have radiotherapy in a special treatment room with a large machine called a linear accelerator (linac). You’ll be asked to lie in a certain position – usually the same way you lay in your planning scan. Your treatment is delivered by radiographers. They’ll help you to get in the right position. Once you’re ready, the radiographers will leave the room and deliver the treatment. They’ll be able to watch you, and you can communicate with them if you need to. Having the treatment usually only takes a few minutes.
Having radiotherapy doesn’t hurt. But you may find it uncomfortable staying in position while you’re having it. Your radiotherapy team will make every effort to make you as comfortable as possible.
Internal radiotherapy
If you’re having internal radiotherapy (brachytherapy), you may need to stay in hospital for a few days.
The implants may be delivered using a needle, a catheter (thin tube) or an applicator. This depends on the part of your body being treated. The implant can be taken out straightaway or it can be left in for a set amount of time. Occasionally, it may be left in permanently, but the radioactivity will gradually wear off.
If you’re having internal radiotherapy, you may need to follow some safety precautions when you go home, until the radioactivity wears off. It’s usually safe to be with other people. But you may need to avoid very close contact with children and pregnant women for a short while. Your radiotherapy team will give you specific advice about this.
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What are the side-effects of radiotherapy?
Radiotherapy affects everyone differently. Some people have mild side-effects. But others find the side-effects are worse. This may depend on:
- which part of your body is being treated
- the type of radiotherapy you have
- how much radiotherapy you have
- and your own health
Your radiotherapy team will do all they can to reduce your chance of getting side-effects. They’ll help you cope if you do get any side-effects.
General side-effects of radiotherapy can include:
- problems with your skin (such as dryness, redness, itching, blistering or peeling) – your doctor may recommend some emollients (moisturisers) or steroid creams that can help
- feeling tired and weak – rest when you need to, but try to keep as active as you can
- losing your hair in the area that’s being treated – this is usually only temporary
Some side-effects may be specific to the part of your body that’s being treated. You may get:
- a dry mouth, difficulty swallowing and a sore mouth if you have radiotherapy to your head and neck
- shortness of breath or an inflammation of the lung called pneumonitis if you have radiotherapy to your chest
- nausea, vomiting and diarrhoea if you have radiotherapy to your tummy
Many of these side-effects do wear off but this can take several weeks.
Sometimes, radiotherapy can leave you with long-term side-effects. These may happen weeks or even years after you finish treatment. There’s also a risk that the radiotherapy itself can cause another cancer. Radiotherapy to your lower abdomen or pelvis can affect your fertility. Your doctor will give you more information about long-term side-effects associated with the type of radiotherapy you’re having. They’ll explain how these may affect you. They’ll also let you know the options available to you.
Is there any follow-up after radiotherapy?
After you’ve finished radiotherapy, you’ll usually have some follow-up appointments with your specialist radiation oncologist. How often you have these appointments will depend on your hospital’s routine. You can contact the radiotherapy team between the appointments if you have any problems as you recover from your treatment.
Your doctor may need to take some X-rays and do some tests to check how the treatment went. They’ll go through the results with you. You’ll also have the chance to discuss any side-effects and anything that’s worrying you.
Having radiotherapy shouldn’t be painful. But you may find it uncomfortable staying in the same position while you’re having it. You may also have some pain afterwards. For more information, read our what happens during radiotherapy? and What are the side-effects of radiotherapy? sections.
Radiotherapy uses high doses of radiation to target and destroy cancer cells. It does this without damaging your healthy cells as much as possible. For more information, see our about radiotherapy section.
Radiotherapy can cause some side-effects. These side-effects may include skin problems, feeling tired and weak, and hair loss. You may get other side-effects too. For more information, see our what are the side-effects of radiotherapy section?
Radiotherapy can be used to try to cure certain cancers. It can also reduce the chance of cancer coming back or to help relieve cancer symptoms. The success rate will depend on the type, stage and location of the cancer and on the radiotherapy dose and number of doses. For more information, see our about radiotherapy section.
An external beam radiotherapy session usually takes less than 30 minutes. If you’re having internal radiotherapy (brachytherapy), you may need to stay in hospital for a few days. For more information, read our what happens during radiotherapy section?
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- Personal communication, Dr Sunil Skaria, Clinical Oncologist, March 2023
