Physical side effects of radiotherapy

Radiotherapy is an effective treatment for many cancers, but it can cause side effects. People react quite differently to radiotherapy, and some people may have no side effects. There are many factors that impact the type and severity of side effects, so it’s not unusual if your side effects are different to someone else having treatment.

Side effects vary depending on the part of the body being treated. Reactions can also change from one period of radiotherapy to the next. Before treatment begins, talk to your radiation oncologist about the possible side effects from the treatment.

During your course of treatment, tell your radiation oncologist, radiation therapist or nurse of any side effects you notice. These can usually be controlled with the right care and medicine.

Most side effects go away in time. Other less common side effects may be permanent, and some may not start until after treatment has finished.

If you have severe side effects, the doctor may change the treatment or prescribe a break in your course of treatment. However, this may not be possible if your doctor thinks pausing the treatment could affect how well it’s working. Check with your doctor.

Always ask your radiation oncologist before using any medicines, home remedies or creams to ease side effects. Some of these remedies can affect how radiotherapy works in your body.


During radiotherapy, your body uses a lot of energy dealing with the effects of radiation on normal cells. Tiredness usually builds up slowly during the course of treatment, particularly towards the end, and may last for a few months after treatment finishes.

Many people find that they cannot do as much, but others are able to continue their usual activities.

  • Do fewer things if you feel tired and spread out daily activities.
  • Rest or take naps during the day if you can.
  • Let family and friends help with shopping, child-care, housework and driving.
  • Take a few weeks off work during or after your radiotherapy, or reduce your hours. You may be able to work at home – discuss your situation with your employer. 
  • Do light exercise, such as walking, and/or keep up with your normal exercise routine. Regular exercise may boost energy levels and make you feel less tired. Talk to your health care team about suitable activities for you.
  • Limit caffeinated drinks like tea, coffee and soft drinks. While they may boost your energy, caffeine can make you feel jittery and irritable. It can also cause insomnia and dehydration.
  • Limit alcohol.
  • Eat a healthy, well-balanced diet, and don’t skip meals.
  • Smoking reduces your energy. If you smoke, talk to your doctor or call Quitline 13 78 48 and ask about stopping.

Skin problems

Radiotherapy may make skin in the treatment area dry and itchy. Your skin may peel and look red, sunburnt or tanned. You may need dressings and creams to assist healing and make you more comfortable. Some of the radiation passes through your body and out the other side, so the skin in that part of your body may also be mildly affected. These reactions fade with time.

  • Follow skin care instructions as soon as treatment starts, even if you haven’t noticed any skin reactions.
  • Ask staff before using any soap, deodorant, perfume, talcum powder, creams, cosmetics, medicines or other products on the treatment area. If needed, you may be prescribed a moisturiser.
  • Wear loose soft clothing, such as cotton. Avoid tight-fitting clothes, belts or close-fitting collars over the treatment area.
  • Tell your doctor about changes to your skin, e.g. cracks or blisters, moist areas, rashes, infections or peeling. 
  • Choose loose, old clothes that you can throw out if the dye or ink marks rub off on them.
  • Stay out of the sun and cover your skin before going outside. Talk to your doctor about using sunscreen – it’s not recommended on sensitive, inflamed or broken skin.
  • Let the dye outlines wear off gradually. Don’t scrub your skin to try to remove the marks.
  • Don’t use razors, hot-water bottles, heat packs, wheat bags or ice packs on the treatment area. Bathe or shower in lukewarm water – hot water can damage your sensitive skin. Pat skin dry with a soft towel.

Hair loss

If you have hair in the area being treated (e.g. scalp, face or body), you may lose some or all of it duringradiotherapy. Your hair will usually grow back a few months after the treatment has finished. Sometimes hair loss is permanent.

In general, you will only lose hair in the treated area. However, when tumours on the face are treated, hair on the back of the head may be lost due to small amounts of radiation passing through the head and out the other side.

  • Wear a wig, toupee, hat, scarf or turban. Do whatever feels comfortable and gives you the most confidence. 
  • If you plan to wear a wig, choose it early in your therapy so you can match it to the colour and style of your own hair. Cancer Council Helpline, your doctor or nurse may be able to help you find a wig.
  • Protect your head against sunburn and the cold if you plan to leave it bare.
  • Expect the hair that grows back to be different, perhaps thinner or curly where it was once straight. After a large dose of radiotherapy, the new growth may be patchy for a while.
  • Ask your hairdresser to make your remaining hair look as good as possible. Your hairdresser may be able to try a new style. In time, your hair will probably return to its normal condition.
  • Contact Look Good…Feel Better. This program teaches techniques to help restore appearance and self-image during treatment. For more details see or call 1800 650 960.


If you have radiotherapy to your stomach region, you may get an upset stomach. This problem will usually get better when your treatment session is over. However, some people feel queasy for a few hours after external radiotherapy. 

  • Have a bland snack, such as toast and apple juice, before treatment.
  • Sip on water and other fluids throughout the day to prevent dehydration.
  • Nibble dry biscuits. 
  • Ask your doctor if a prescription for anti-nausea medication would help you.
  • Take anti-nausea medication before, during or after treatment, as prescribed by your doctor.
  • Tell your doctor if medicine doesn’t help – it may take some time to find medication that works for you.
  • Contact your doctor if you still feel nauseated after a few days, or are vomiting for more than 24 hours.
This information was last reviewed in February 2014
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