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Radiation therapy


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. Radiation therapy is a localised treatment, which means it generally affects only the area being treated.

Radiation therapy is an important part of treating cancer. It’s estimated that radiation therapy would be a suitable treatment for 50% of people with cancer. It can be used in three main ways: 

  • To achieve remission or cure – given as the main treatment to cause the cancer to reduce (remission) or disappear (curative or definitive radiation therapy). Sometimes definitive radiation therapy is given together with chemotherapy to make it work better (chemoradiation).
  • To help other treatments – often used before other treatments (neoadjuvant) to shrink the tumour or after other treatments (adjuvant) to kill any remaining cancer cells.
  • To relieve symptoms – can help to relieve pain and other symptoms by making the cancer smaller or stopping it from spreading (palliative treatment).

How it works

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.

There are two 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) – radiation beams from a large machine called a linear accelerator are precisely 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. 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.

Treatment is carefully planned to do as little harm as possible to healthy cells near the cancer. Most of these cells tend to receive a lower dose and can usually repair themselves. 

Having treatment

Radiation therapy is usually given in the radiation oncology department of a hospital or in a treatment centre. This may be in the public or private health system. Most people have radiation therapy as an outpatient. This means you do not stay in hospital, but travel to the hospital or treatment centre for each session. For some types of internal radiation therapy, you may need to stay in hospital overnight or for a few days. 

If you are having radiation therapy with the aim of making the cancer go away, you may have treatment for 5–7 weeks. Usually treatment is once a day, Monday to Friday, but sometimes it’s given twice a day. Your doctor will tell you how many treatments you will have.

If you live a long way from the treatment centre and you’re having a short course, your treatment may be given two or three times per week.

Knowing if 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 you straightaway how the cancer is responding. After treatment finishes, you will have regular check-ups. Your radiation oncologist will do a physical examination and arrange tests or scans to check how the cancer has responded to treatment.

You may not know the full benefit of having radiation therapy for some months. If radiation therapy is given as palliative treatment, the relief of symptoms is a good sign that the treatment has worked. This may take a few days or weeks. Until then, you may need other treatments for your symptoms, for example pain medicine.

Life after treatment

For most people, the cancer experience doesn’t end on the last day of radiation therapy. Radiation therapy usually does not have an immediate effect, and it could take days, weeks or months to see any change in the cancer.

After radiation therapy has finished, your treatment team will tell you how to look after the treatment area and recommend ways to manage side effects. You will have regular check-ups with the radiation oncologist at the treatment centre. These will become less frequent over time. You will receive continued support from allied health professionals, such as a dietitian, physiotherapist or speech pathologist, if you need it. 

Let your treatment team know immediately if you have any health problems between follow-up appointments. Many of the long-term or late effects of radiation therapy can be managed better if identified early. 



Chemoradiation means having radiation therapy at the same time as chemotherapy, and it increases the success of the treatment compared with having either treatment on its own. This is because the chemotherapy drugs make the cancer cells more sensitive to radiation therapy.

Chemoradiation is only used to treat some cancers. If you have chemoradiation, you will usually receive chemotherapy a few hours before some radiation therapy appointments.

The side effects of chemoradiation depend on the type of chemotherapy you have and on the radiation therapy treatment area. Your radiation therapy team can provide support and information about how to manage any side effects you develop. 

Learn about common side effects

Health professionals

During and after treatment, you will see a range of health professionals who specialise in different aspects of your cancer care. The main specialist doctor for radiation therapy is a radiation oncologist. You may be referred to a radiation oncologist by your general practitioner (GP) or by another specialist such as a surgeon or medical oncologist.

Treatment options will often be discussed with other health professionals at what is known as a multidisciplinary team (MDT) meeting. You may also see some allied health professionals, such as a speech pathologist, occupational therapist and exercise physiologist, to help you manage any treatment side effects. 

Question checklist

Asking your doctor questions will help you make an informed choice. You may want to include some of the questions below in your own list:

  • Why do I need radiation therapy?
  • What are the advantages and disadvantages of radiation therapy for me?
  • How successful is radiation therapy for the type of cancer I have?
  • What kind of radiation therapy will I have?
  • Will it be my only treatment, or will I have other treatments?
  • How long will treatment take? How will it be given?
  • Where can I have this treatment? Will I have to travel away from home?
  • Will I have radiation therapy as an inpatient or outpatient?
  • How will I know if the treatment is working?
  • Are there any out-of-pocket expenses not covered by Medicare or my private health cover? Can the cost be reduced if I can’t afford it?
  • Are there clinical guidelines you are following?
  • Are there any clinical trials or research studies I could join?
Side effects
  • What are the risks and possible side effects of radiation therapy?
  • Will any side effects be long-term or short-term?
  • Will I be radioactive? Will my partner be affected?
  • Is it safe to have sex during the course of radiation therapy?
  • Will radiation therapy interact with any other medicines or vitamins I take?
  • Can I work, drive and do my normal activities while having treatment?
  • Are there any complementary therapies that might help me?
  • Should I change my diet or physical activity during or after treatment?
  • Who should I contact if I have a problem during treatment? Who is my after-hours contact?
After treatment
  • How often will I need check-ups after treatment?
  • If the cancer returns, how will I know? What treatments could I have?


Steps in radiation therapy

  1. Consultation session – you will meet with a radiation oncologist. They will check your test results, assess your fitness for treatment, explain the process and expected results, and discuss possible side effects and risks. You will be asked to agree (consent) to have treatment.
  2. Planning session – you will meet with a radiation therapist. They will work out how to best position your body during EBRT or where to place the applicators for brachytherapy.
  3. Treatment plan – based on the planning session and the treatment guidelines for your cancer type, the radiation oncologist, radiation therapist and medical physicist will work out the radiation dose, what area needs to be treated and how to deliver the right dose of radiation.
  4. Treatment sessions – radiation therapists will deliver the course of radiation therapy as set out in the treatment plan. How long each treatment session takes will depend on the type of radiation therapy. 
  5. Review and follow-up – you will have regular reviews during treatment to monitor and discuss how to manage any side effects. After radiation therapy ends, you will see the radiation oncologist to find out whether the cancer has responded to treatment.

Preparing for radiation therapy

The side effects of radiation therapy depend on the part of the body being treated, the radiation dose and the number of treatments you need. It can be hard to know how to prepare, but several issues are worth thinking about in advance. 

Ask about pregnancy and fertility

Some types of radiation therapy affect fertility. If you think you may want to have children in the future, talk to your treatment team about your options before radiation therapy begins. 

You probably won’t be able to have radiation therapy if you are pregnant, as radiation can harm a developing baby. It’s also important that you don’t become pregnant during the course of treatment. If at any time you suspect you may be pregnant, it is important to tell your doctor. If you are breastfeeding, ask your doctor whether it is safe to keep breastfeeding while you’re having radiation therapy.

It is recommended that people who have radiation therapy to the pelvic area avoid getting their partner pregnant during treatment and for about six months afterwards, as radiation therapy can damage sperm. Your doctor will be able to give you more information about radiation therapy and pregnancy.

Explore ways to relax 

Read a book or listen to music while you wait, ask a friend or family member to keep you company, or try chatting to other people waiting for treatment. To help you relax during the session, try breathing exercises or meditation, or ask the radiation therapists if you can listen to music. 

Organise help at home

Support with housework and cooking can ease the load. If you have young children, arrange for someone to look after them during radiation therapy sessions. Older children may need someone to drive them to and from school and activities. Ask a friend or family member to coordinate offers of help, or use an online tool such as The CanDo app and Gather My Crew.  

Consider quitting

If you smoke, it is important to stop smoking before starting treatment. Smoking may mean the treatment doesn’t work as well and it can make side effects worse. If you need support to quit smoking, talk to your doctor or call the Quitline on 13 7848.

Arrange transport and accommodation

Plan how you will get to radiation therapy sessions. If travelling by car, ask about parking. You are likely to feel more tired as the treatment goes on, so arrange for someone to drive you. If you have to travel a long way for radiation therapy, you may be eligible for financial assistance to help cover the cost of travel or accommodation.

Call 13 11 20 to find out if there is a transport to treatment service or accommodation service in your area and how to access patient travel assistance.

Look after your body

If you are having radiation therapy for a cancer in the head and neck region, visit your dentist for a check-up before radiation therapy begins. The dentist can check for any teeth that may cause an infection and advise if they need to be removed before you start treatment.

Let your treatment team know if you have any medical devices in your body. This may be a pacemaker, cochlear implant or metal implant, such as a hip or knee replacement. Radiation therapy can affect these devices or be affected by them.

Your treatment team will encourage you to be as active as possible as this can help you feel better. Research shows that exercise can help manage ongoing effects of radiation therapy, including fatigue

Check the costs

If you receive radiation therapy as an outpatient in a public hospital, Medicare pays for your treatment. Medicare also covers some of the cost of radiation therapy in private clinics, but you may have to pay the difference between the cost of treatment and the Medicare rebate (gap payment).

Private health insurance does not usually cover radiation therapy, as it’s considered an outpatient treatment. Before treatment starts, ask your provider for a written quote that shows what you will have to pay.


Working during radiation therapy

Whether you will be able to work depends on the type of radiation therapy you have, how the treatment makes you feel and the type of work you do. Ask your treatment team if they offer very early or late appointments so that you can fit your treatment appointments around your work.

Let your employer know about how much time you are likely to need off work. Explain that it is hard to predict how radiation therapy will affect you, and discuss the options of flexible hours, modified duties or taking leave.

Learn more about cancer and work


Understanding Radiation Therapy

Download our Understanding Radiation Therapy booklet to learn more.

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Expert content reviewers:

Prof June Corry, Radiation Oncologist, GenesisCare, St Vincent’s Hospital, VIC; Prof Bryan Burmeister, Senior Radiation Oncologist, GenesisCare Fraser Coast, Hervey Bay Hospital, and The University of Queensland, QLD; Sandra Donaldson, 13 11 20 Consultant, Cancer Council WA; Jane Freeman, Accredited Practising Dietitian (Cancer specialist), Canutrition, NSW; Sinead Hanley, Consumer; David Jolly, Senior Medical Physicist, Icon Cancer Centre Richmond, VIC; Christine Kitto, Consumer; A/Prof Grace Kong, Nuclear Medicine Physician, Peter MacCallum Cancer Centre, VIC; A/Prof Sasha Senthi, Radiation Oncologist, The Alfred Hospital and Monash University, VIC; John Spurr, Consumer; Chris Twyford, Clinical Nurse Consultant, Radiation Oncology, Cancer Rapid Assessment Unit and Outpatients, Canberra Hospital, ACT; Gabrielle Vigar, Nurse Unit Manager, Radiation Oncology/Cancer Outpatients, Cancer Program, Royal Adelaide Hospital, SA. 

Page last updated:

The information on this webpage was adapted from Understanding Radiation Therapy - A guide for people with cancer, their families and friends (2021 edition). This webpage was last updated in February 2022. 

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