Radiotherapy
Radiotherapy means the use of radiation, usually x-rays, to treat cancer. You might have radiotherapy from inside the body, called internal radiotherapy. Or external radiotherapy, which is from outside the body.
You may have radiotherapy:
to try to cure cancer
reduce the chance of cancer coming back
to help relieve symptoms
You might have it by itself or with other treatments, such as chemotherapy or surgery.
Most types of radiotherapy use photons. But you might have electrons or more rarely protons. Your doctor decides which type you need.
Find out more about internal or external radiotherapy
Radiotherapy is a type of ionising radiation (high energy) that destroys cancer cells in the treated area by damaging the of these cells. Radiation also affects normal cells. This can cause side effects in the treatment area.
Usually the side effects improve a few weeks after treatment. But some might continue long term. Your doctor will talk this through with you before you start treatment. They will also discuss possible ways of managing side effects.
Find out more about the side effects of radiotherapy
Your radiotherapy treatment plan is individual to you.
It aims to give a high dose of radiation to the cancer but as low a dose as possible to the surrounding healthy cells. This gives the highest chance of curing or shrinking the cancer, while reducing the risk of side effects.
When deciding on your course of treatment your doctor takes into account:
your type of cancer
the position of the cancer in your body
any other treatment you've had, are having, or is planned for you
your general health and fitness
Radiotherapy with the aim of curing cancer usually lasts between 1 to 7 weeks.
For radiotherapy to relieve symptoms, you might have anything between a single treatment to 2 weeks of treatment. It might be longer than this. Your doctor will tell you how many treatments you’ll have.
Most people have daily treatment from Monday to Friday, with a rest at weekends. But this can vary. For example, you might have treatment once a week for a set number of weeks. It is also sometimes possible to have more than one treatment per day.
Let your therapeutic radiographer know if you have any commitments, such as work or childcare, that mean you need a specific time for your appointments. They will try to be as flexible as possible, but it can be difficult depending on how busy the department is.
You may feel anxious about radiotherapy and this is normal. It can help to talk through any worries you have with your doctor, nurse or radiographer.
Find out more about coping with cancer
That Cancer Conversation is Cancer Research UK's podcast.
In the episode exploring radiotherapy and cancer we explain what radiotherapy is. And we talk about the history and evolution of radiotherapy. We speak to Nevo, an image consultant and stylist who was diagnosed with in 2012 and had radiotherapy as part of her cancer treatment.
Last reviewed: 04 Oct 2023
Next review due: 05 Oct 2026
External radiotherapy targets radiation at the cancer from a radiotherapy machine. Read about types of external radiotherapy and what happens during planning.
Internal radiotherapy means having radiation treatment from inside the body. It is also called brachytherapy. Read more about what it is and how you have it.
Radiotherapy can cause different side effects depending on which part of the body is being treated. Find out what these side effects are and how they affect you during and after treatment.
People with pacemakers can usually have radiotherapy. But a nurse or trained radiographer might monitor the pacemaker before, during and after treatment if the pacemaker is directly in the radiotherapy field.
Find out about cancer treatment with radiotherapy, including external radiotherapy, internal radiotherapy, side effects, radiotherapy for symptoms and follow up after treatment.
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