Radiation therapy uses a controlled dose of radiation to kill cancer cells or damage them so they cannot grow, multiply or spread. The radiation is usually in the form of focused x-ray beams, also known as photons. It can also be in other forms such as electron beams, proton beams or gamma rays from radioactive sources. It is localised treatment, which means it generally affects only the part of the body where the radiation is targeted.
On this page you will find information on:
- How does radiation therapy work?
- Why have radiation therapy?
- How is radiation therapy given?
- How do I know if the treatment has worked?
- What are the side effects?
How does radiation therapy work?
Radiation therapy kills or damages 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. Although the radiation can also damage healthy cells, these tend to be less sensitive than the cancer cells and can usually repair themselves.
Why have radiation therapy?
Research shows that about one in two people with cancer would benefit from radiation therapy. It can be used for different reasons:
- As the main treatment to achieve remission or cure. Radiation therapy may be given with the aim of causing the signs and symptoms of cancer to reduce or disappear. This is called curative or definitive radiation therapy.
- To help other treatments achieve remission or a cure. Radiation therapy is often used before (neoadjuvant) or after (adjuvant) treatments such as surgery to make the treatment more effective. It can also be used at the same time as some treatments; when it is combined with chemotherapy it is know as chemoradiotherapy.
- For symptom relief. Radiation therapy can help to relieve other symptoms by making the cancer smaller or stopping it from spreading. This is known as palliative treatment.
How is radiation therapy given?
Radiation therapy can be given in two ways:
- External beam radiation therapy. Radiation beams from a large machine are aimed at the area of the body where the cancer is located. The process is similar to having an x-ray.
- Internal radiation therapy – A radiation source is placed inside the body, or more rarely, injected into a vein, or swallowed.
You may have one or both types of radiation therapy, depending on the type of cancer and other factors.
For more details on external and internal radiation therapy refer to Understanding Radiation Therapy booklet.
How will I know the treatment has worked?
Because cancer cells continue to die for weeks or months after treatment ends, your radiation oncologist most likely won’t be able to tell how the cancer is responding. However, they can help you manage any side effects.
After treatment is finished, you will have regular check-ups. Your radiation oncologist will do a physical examination, and arrange tests or scans to check whether the cancer has responded to treatment. It may be some time after radiation therapy finishes before the full benefit is known.
If radiation therapy is given as palliative treatment, the relief of symptoms will indicate that treatment has worked. This may take a few days or a few weeks.
What are the side effects?
Radiation therapy is an effective treatment for many cancers, but it can also injure healthy cells at or near the treatment area. This can lead to side effects. Some people experience many side effects, while others have very few or none. Many factors can affect the type and severity of side effects including; the type or radiation therapy; the dose of the radiation needed; any other treatments you might be having; and your general health.
Common side effects of radiation therapy may include:
- Appetite loss
- Skin problems
- Hair loss
- Bladder problems
- Bowel problems
- Sexuality and intimacy issues
- Mouth and throat problems
- Tissue hardening (fibrosis)
For more information on radiation therapy please refer to the Understanding Radiation Therapy booklet.
The information available on this page should not be used as a substitute for advice from a properly qualified medical professional who can advise you about your own individual medical needs. It is not intended to constitute medical advice and is provided for general information purposes only. See our Disclaimer.