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Radiation therapy, also known as radiotherapy, is one of the main treatments for cancer. Being prepared and understanding radiation therapy can help lessen some of the stress surrounding your treatment. Ask your oncologist, doctor or nurse about the risks and benefits of radiation therapy and any other questions you have about your treatment.

See our understanding radiotherapy booklet also available as an epub.

What is radiation therapy used for?

Radiation therapy uses X-rays to destroy or injure cancer cells so they cannot multiply. Radiation therapy can be used to treat the primary cancer or advanced cancer.

It can also be used to reduce the size of the cancer and relieve pain, discomfort or other symptoms.

When is radiation therapy used?

Radiation therapy may be the main treatment, or may be used to assist another treatment. Adjuvant radiation therapy may be used to shrink the cancer before surgery, or after surgery, to stop the growth of any remaining cancer cells. In some cases it is used with chemotherapy.

Why is radiation therapy given?

Radiation therapy may aim to:

  • cure - some cancers can be cured by radiation therapy alone or combined with other treatments.
  • control - radiation therapy can control some cancers by making them smaller or stopping them from spreading.
  • help other treatments - radiotherapy can be used before or after other treatments to make them more effective
  • relieve symptoms - if cure is not possible, radiation therapy may be used to reduce cancer symptoms and prolong a good quality of life.

How is radiation therapy given?

Radiation therapy is given from outside (external beam) or inside the body (brachytherapy). In external beam radiation therapy, a machine directs radiation at the cancer and surrounding tissue. In internal radiation therapy, radioactive material is put in thin tubes and placed in your body near the cancer.

Where will treatment take place?

Radiotherapy is usually given in private clinics or large hospitals. Treatment is given by trained staff called nuclear medicine specialists or radiation therapists. The treatment will be supervised by radiation oncologists who are the main treating medical specialists for people getting radiotherapy.

How long is a course of treatment?

Your treatment will depend on what sort of cancer you have, where it is, its size, your general health and other cancer treatments you may have had. Some people need only one treatment, while others need radiation therapy five days a week for several weeks. If you have internal radiation therapy the implants may be left in place for a few minutes, one to six days or permanently.

Does radiation therapy hurt?

External radiation therapy won't hurt. You won't see or smell the radiation, however you may hear a buzzing sound when the machine is on. You will NOT be radioactive. It is safe to be in contact with other people, including pregnant women and children, when you are having treatment and afterwards.

During internal radiation therapy you may experience a little discomfort from the implant, however you should not have any severe pain or feel ill. While your radioactive implant is in place, it may send some radiation outside your body. There will be limits on visitors while your implant is in place.

What are the side-effects of radiation therapy?

Side-effects vary and will depend on which area of your body is being treated. Possible side-effects include

  • fatigue (tiredness)
  • dry, red or itchy skin
  • loss of appetite
  • nausea (feeling sick)
  • digestive problems
  • hair loss
  • dry or sore throat or mouth
  • cough or shortness of breath.

Most side-effects can be managed and will gradually disappear once your treatment has finished.

How long will side effects last?

In time, most side effects go away. However, some may be permanent and others may not appear until after treatment has finished.

If the side effects are severe, the radiation oncologist may change the treatment or prescribe a break. If the doctor thinks pausing treatment could affect how well the treatment is working then a break may not be possible.

How will I know the treatment has worked?

After treatment finishes, you will have regular check-ups with your doctor. You will have a physical examination, and you may have scans or tests to check whether the cancer has responded to treatment. It may take some time after your radiotherapy treatment has finished before the full benefit is known. 

Your medical team won't be able to give you progress updates during treatment because cancer cells continue to die for weeks or months after treatment ends. They can, however, help you manage any side effects.

If radiotherapy is given as palliative treatment, the relief of symptoms will indicate that the treatment has worked. This may take a few days or weeks.

Will radiation therapy affect my fertility?

Having radiation therapy in areas near your reproductive organs can affect your fertility temporarily or permanently.

Discuss this possibility with your doctor or specialist.

Remember, if you have any concerns or questions, please contact your doctor.

Can I have radiotherapy if I am pregnant?

If you are pregnant, you will probably not be able to have radiotherapy, as radiation can harm a developing baby. It's important that you don't become pregnant during treatment. Men who have radiotherapy should avoid getting their partner pregnant during treatment and for about six months afterwards, as radiation can damage sperm. Your doctor will be able to give you more information about radiotherapy and pregnancy.

Will I be able to work during radiotherapy?

Some people can continue to work during radiotherapy treatment, while others may need to reduce their hours or take time off. How much you are able to work depends on the type of radiotherapy you have, how the treatment makes you feel and the type of work you do. Your treatment team will encourage you to be as active as possible, and they can answer your questions about working during treatment.

Will I be radioactive?

External radiotherapy does not make you radioactive because the radiation does not stay in your body during or after treatment. You will not need to take any special precautions with bodily fluids, and it is safe for you to be with family, friends, children and pregnant women.

Which health professionals will I see?

Your treatment team will be made up of health professionals who care for people having radiotherapy. You will also see other health professionals who specialise in diagnosing and treating the type of cancer you have.

These may include:

  • radiation oncologist
  • radiation therapist
  • medical physicist
  • radiation oncology nurses
  • dietitian
  • social worker/psychologist
  • physiotherapist/occupational therapist.

Where can I get reliable information?

Cancer Council 13 11 20
Information and support for you and your family for the cost of a local call anywhere in Australia.


For more information


Understanding Radiotherapy - Download ebook or PDF

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This page was last updated on: Tuesday, February 19, 2013

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