Radiation therapy uses a controlled dose of radiation to kill cancer cells or damage them so they cannot grow, multiply or spread. Most forms of radiation therapy use focused, high-energy x-ray beams (also known as photons). Radiation can also be electron beams, proton beams, or gamma rays from radioactive sources. Radiation therapy is a localised treatment. This means it generally affects only the area being treated.
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When is radiation therapy used?
It is estimated that radiation therapy would be a suitable part of treatment for 1 in 2 people with cancer. The Guides to Best Cancer Care set out the recommended treatment pathways in Australia for many types of cancer. For some cancers, radiation therapy is recommended as the most effective approach, either on its own or in combination with other treatments. For other cancers, other treatments may be more effective. For more on this, see cancer.org.au/cancercareguides.
How does radiation therapy work?
Radiation therapy aims to kill or damage cancer cells in the area being treated. Cancer cells begin to die days or weeks after treatment starts, and continue to die for weeks or months after it finishes. Treatment is carefully planned to do as little harm as possible to healthy cells near the cancer. Most of these cells receive a lower dose and can usually repair themselves.
Why have radiation therapy?
Radiation therapy can be used for different reasons:
| To achieve remission or cure | Radiation therapy may be given as the main treatment to make the cancer reduce or disappear. This is known as curative or definitive radiation therapy. Sometimes definitive radiation therapy is given together with chemotherapy to make it work better. This is called chemoradiation. |
| To help other treatments | Radiation therapy is often used before or after other treatments. If used before (neoadjuvant therapy), the aim is to shrink a tumour. If used after (adjuvant therapy), the aim is to kill any remaining cancer cells. |
| To relieve symptoms | Radiation therapy may be used to make the cancer smaller or stop it spreading. This is known as palliative radiation therapy. It can help relieve pain and other symptoms. |
Will I have side effects?
If radiation therapy injures healthy cells near the treatment area, side effects may occur. The side effects you have will vary depending on the part of the body treated, the dose of radiation and the length of treatment. Most side effects are temporary and tend to improve gradually in the weeks after treatment ends.
Learn more about managing side effects.
What is chemoradiation?
Chemoradiation means having radiation therapy at the same time as chemotherapy. It is also known as chemoradiotherapy.
The chemotherapy drugs make the cancer cells more sensitive to the radiation. Having radiation therapy and chemotherapy together is more effective for some cancers.
Chemoradiation is only helpful for some cancer types. If you have chemoradiation, your treatment team will talk to you about your treatment plan. You may have chemotherapy and radiation therapy at different times on the same day or on separate days.
The side effects of chemoradiation will vary depending on the chemotherapy drugs you have, the dose of radiation, the part of the body being treated and the length of treatment. Your treatment team will talk to you about what to expect and how to manage any side effects.
How is radiation therapy given?
There are 2 main ways of giving radiation therapy – from outside the body or inside the body. You may have one or both types of radiation therapy, depending on the cancer type and other factors.
| External beam radiation therapy (EBRT) | The process is similar to having an x-ray. You will lie on a treatment table underneath a large machine that moves around your body. Radiation beams from the machine are precisely aimed at the area of the body where the cancer is located. The beam operates for a few minutes only. You won’t see or feel the radiation, although the machine can make noise as it moves. For more information, see EBRT. |
| Internal radiation therapy | A radiation source is placed inside the body or, more rarely, injected into a vein or swallowed. The most common form of internal radiation therapy is brachytherapy, where temporary or permanent radiation sources are placed inside the body next to or inside the cancer. For more information, see Brachytherapy. |
Radiation therapy for children
The information in this section is for adults having radiation therapy. Much of it will also be relevant for children. Talk to your treatment team for specific information about radiation therapy for children, and check out:
- Cancer Hub – Provided by Canteen, Redkite and Camp Quality, this website helps families affected by cancer (with children aged up to 25 years) get support. Call 1800 431 312.
- Cancer Australia Children’s Cancer – For information about how children’s cancers and how they are treated.
- Talking to Kids About Cancer – Explaining a cancer diagnosis to kids can feel overwhelming. This information can provide a starting point for these often challenging conversations. You can also listen to our podcast episode, Explaining Cancer to Kids.
→ READ MORE: Common questions about radiation therapy
Video: What is radiation therapy?
Watch this short video to learn more about radiation therapy (also known as radiotherapy).
Podcast: Making Treatment Decisions
Listen to more episodes from our podcast for people affected by cancer
Key resource
Download a PDF booklet on this topic.
More resources
A/Prof Susan Carroll, Senior Staff Specialist, Radiation Oncology, Royal North Shore Hospital, and The University of Sydney, NSW; Katie Benton, Advanced Dietitian Oncology, Sunshine Coast Hospital and Health Service, QLD; Adrian Gibbs, Director of Physics, Radiation Oncology, Princess Alexandra Hospital Raymond Terrace, QLD; Sinead Hanley, Consumer; Dr Annie Ho, Radiation Oncologist, GenesisCare, Macquarie University Hospital and St Vincent’s Hospital, NSW; Angelo Katsilis, Clinical Manager Radiation Therapist, Department of Radiation Oncology, Royal Adelaide Hospital, SA; Candice Kwet-On, 13 11 20 Consultant, Cancer Council Victoria; Jasmine Nguyen, Radiation Therapist, GenesisCare Hollywood, WA; Graham Rees, Consumer; Nicole Shackleton, Radiation Therapist, GenesisCare Murdoch, WA; Dr Tom Shakespeare, Director, Cancer Services, Mid North Coast Local Health District, NSW; Gabrielle Vigar, Nurse Lead, Cancer Program, Royal Adelaide Hospital and Queen Elizabeth Hospital, SA.
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