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Managing side effects

Radiation therapy can treat many cancers, but it can also injure healthy cells at or near the treatment area. This can lead to side effects. Before recommending any treatment, the radiation oncologist will consider whether the potential benefits outweigh the possible side effects. To minimise side effects, a range of new techniques have made radiation therapy highly precise. This section provides information and tips to help you manage some common side effects of radiation therapy.

Preparing for side effects

Some people experience many side effects, while others have very few or none. Side effects can vary even among people having the same type of radiation therapy to the same part of the body. Many factors can affect the type and severity of side effects, including:

  • the part of the body treated
  • the type of radiation therapy
  • the dose of radiation needed
  • any other treatments you might be having
  • your general health.

Most side effects that occur during treatment are manageable. Before treatment begins, your radiation therapy team will discuss how to look after the treatment area, the side effects to watch out for or report, ways to manage them, and who to contact after hours if you need help.

If you have severe side effects, the radiation oncologist may change the treatment or arrange a break. They may not recommend these options if it would affect how well the treatment works.

It is important to maintain your general health during treatment. People who have diabetes need to manage their condition so it doesn’t affect their recovery – see your GP before treatment starts.

How long side effects may last

Radiation therapy can cause side effects during and just after treatment – these are called short-term or acute effects. It can also cause long-term or late effects months or years down the track.

Short-term side effects
Side effects often build up gradually during treatment and it could be a few days or weeks before you notice anything. Often the full impact comes at the end of treatment or even a week or two afterwards.

During treatment, tell your radiation oncology team about any side effects, as side effects can usually be controlled with the right care and medicine. Most side effects are temporary and go away in time, usually within a few weeks of treatment finishing

Long-term or late effects
Radiation therapy can also cause effects months or years after treatment. These late effects are usually mild, they may come and go, and they may not have any major impact on your daily life. However, they may be more significant. Some may go away or improve on their own, while others may be permanent and need to be treated or managed.

Very rarely, years after successful treatment, patients can develop a new unrelated cancer in or near the area treated. The risk of this late effect is very low, but other factors, such as continuing to smoke or very rare genetic conditions, can increase this risk.

Radiation therapy to the chest, particularly when combined with chemotherapy, may lead to an increased risk of heart problems. Newer radiation therapy techniques have reduced the risk, however, talk to your doctor about your heart health. If you develop heart problems later in life, make sure you let your doctors know you had radiation therapy.

Common side effects

The side effects of radiation therapy often relate to the type of cancer and the part of the body treated, so it can be useful to download and read the booklet about the type of cancer you have or call 13 11 20 to ask for a copy.

Feeling very tired and lacking energy for day-to-day activities is a common side effect of radiation therapy to any area of the body. During treatment, your body uses a lot of energy dealing with the effects of radiation on normal cells. Fatigue can also be caused by travelling to daily treatment sessions and other appointments. It usually builds up slowly during the course of treatment, particularly towards the end, and may last for some weeks or months after treatment finishes. Many people find that they cannot do as much as they normally would, but others are able to continue their usual activities.

How to manage fatigue

  • Listen to your body. If you feel tired, rest.
  • Try to spread activities out through the day.
  • Ask family and friends for help, e.g. with shopping, housework and driving.
  • Take a few weeks off work during or after treatment, reduce your hours, or work from home. Discuss your situation with your employer.
  • Do some regular exercise, such as walking. Moderate intensity exercise can boost energy levels and make you feel less tired. Talk to your treatment team about suitable activities for you.
  • Limit caffeinated drinks, such as cola, coffee and tea. While caffeine may give a burst of energy, it can make you feel jittery and irritable, and cause insomnia and dehydration.
  • Limit your alcohol intake. If you smoke, try to quit.
  • Eat a healthy, well-balanced diet, and don’t skip meals.

Download our fact sheet ‘Fatigue and Cancer’

Depending on the part of the body treated, external beam radiation therapy may make skin in the treatment area dry and itchy. Your skin may look  red, sunburnt or tanned. Less commonly, it may peel and feel painful. Skin changes often start 10–14 days after the first treatment. They often get worse during treatment, before improving in the weeks after treatment. You may need dressings and creams to help the area heal, avoid infection and make you more comfortable. Pain medicine can help if the skin is very sore. Let your radiation therapy team know about skin changes, such as cracks or blisters, moist areas, rashes, infections, swelling or peeling.

Taking care of your skin

  • Follow the treatment team’s instructions about which creams to use and how to look after your skin. Do this once treatment starts, even before you notice any skin changes.
  • Check with your treatment team before using any over-the-counter moisturising creams.
  • Avoid using razors, hair dryers, hot water bottles, heat packs, wheat bags or icepacks on the treatment area.
  • Bathe or shower in lukewarm water, as hot or very cold water can irritate sensitive skin. Do not use harsh soaps or other products. Pat skin dry with a soft towel.
  • Let skin markings wear off gradually. Don’t scrub your skin to remove them.
  • Wear loose, soft cotton clothing. Avoid tight-fitting items, belts, underwire bras, jewellery or collars over the treatment area.
  • Cover your skin before going outside and stay out of the sun.
  •  Avoid chlorinated swimming pools, spas and saunas.

If you have hair in the area being treated, you may lose some or all of it during or just after radiation therapy. The hair will usually grow back a few months after treatment has finished, but sometimes hair loss is permanent.

When cancers on one part of the face or head are treated, hair on the other side of the head may be lost temporarily due to radiation passing from one side to the other.

Ways to manage hair loss

  • If you are having radiation therapy to your head or scalp area, think about cutting your hair short before treatment starts. This will make any hair loss easier to manage.
  • Wear a wig or toupee, or leave your head bare. Do whatever feels comfortable and gives you the most confidence.
  • If you prefer to leave your head bare, wear a hat, beanie, turban or scarf to protect your scalp against sunburn and the cold.
  • If you plan to wear a wig, choose it before treatment starts so you can match your own hair colour and style. Call Cancer Council 13 11 20 for information about wig services.
  • As your hair grows back, talk to your hairdresser or barber about how to style it. It may be thinner, or curly where it was once straight, and the new growth may be patchy for a while.
  • Contact Look Good Feel Better. This program teaches people how to manage the appearance-related side effects caused by cancer treatment. Call 1800 650 960 or visit

Download our fact sheet ‘Hair Loss’

Good nutrition is important during and after cancer treatment. It can help to manage the side effects of treatment and speed up recovery. However, some people may lose interest in food or find it difficult to eat well during radiation therapy. This can depend on the part of the body being treated. It is important to try to keep eating well so you get the nourishment you need to maintain your weight.

If the radiation therapy is directed near your abdomen, pelvic region or head, you may feel sick (nauseated) with or without vomiting for several hours after each treatment. Your radiation oncologist may prescribe medicine to take at home before and after each session to prevent nausea. If you are finding nausea difficult to manage, talk to the radiation oncologist or nurse, or call
Cancer Council 13 11 20.

If you have radiation therapy to the head and neck area, chewing or swallowing may be difficult or painful. Your sense of taste may also change if radiation therapy has affected the salivary glands or tastebuds. In some cases, taste changes may be permanent.

If you are finding it difficult to eat well and get the nutrition you need, a dietitian can suggest changes to your diet, liquid supplements or a feeding tube. This will help improve your strength, lessen side effects, and lead to better treatment outcomes.

How to manage appetite changes

Appetite loss

  • Eat 5–6 small meals each day rather than a few large meals.
  • Try to eat extra on days when you have an appetite.
  • Ask a dietitian for advice on the best eating plan during treatment and recovery.
  • If you don’t feel like eating solid foods, try enriching your drinks with powdered milk, yoghurt, eggs or honey.
  • Do not use nutritional supplements or medicines without your doctor’s advice, as some could interfere with treatment.
  • Cooking smells may put you off eating. It might help if someone else prepares your food, or you could reheat precooked meals.
  • Try to do some light physical activity, such as walking. This may improve your appetite.


  • Have a bland snack, such as toast and apple juice, before each session.
  • You may find that food and drinks with ginger or peppermint help to reduce nausea.
  • Sip on water and other fluids throughout the day to prevent dehydration.
  • Eat dry biscuits, crackers or toast.
  • Some people find that anti-nausea medicine helps. Ask your doctor for a prescription. Tell them if the prescribed medicine doesn’t help – it may take some time to find one that works for you.
  • Contact your treatment team if the symptoms of nausea don’t improve after a few days, or if you have been vomiting for more than 24 hours.

Download our booklet ‘Nutrition and Cancer’

Radiation therapy is often used to treat cancer in the mouth, throat, neck or upper chest region. Depending on the area treated, radiation therapy may affect your mouth and teeth. This can make eating and swallowing difficult, and change your sense of taste.

Teeth problems

Radiation therapy to the mouth may increase the chance of tooth decay or other problems in the future. You will need to have a thorough dental check-up and may need to have any decaying teeth removed before treatment starts.

Your dentist can provide an oral health care plan, which outlines any dental work you need before having radiation therapy. It also provides detailed instructions about how to care for your mouth to help prevent tooth decay and deal with side effects such as mouth sores. You will need regular dental check-ups after treatment ends to help prevent future problems.

Dryness and other issues

After several weeks of treatment, your mouth or throat may become dry and sore, and your voice may become hoarse. Radiation therapy can affect your salivary glands so you produce less saliva, which can contribute to a dry mouth. These effects will gradually improve after treatment finishes, but it may take several weeks or even months. In some cases, the effects may improve but not completely disappear. Dry mouth (xerostomia) can make chewing, swallowing and talking difficult. A dry mouth can also make it harder to keep your teeth and mouth clean, which can increase the risk of tooth decay.

How to relieve mouth and throat problems

  • Have a dental check-up before treatment begins with a dentist who specialises in the effect radiation therapy has on teeth. Your radiation oncologist can provide a referral.
  • Keep your mouth moist in between treatments by sucking on ice chips and sipping cool drinks. Carry a bottle of water with you.
  • Ask your doctor, nurse or pharmacist for information about artificial saliva to moisten your mouth.
  • If you have a dry mouth, you may need to avoid rough, crunchy or dry foods (e.g. chips, nuts, toast, dry biscuits); salty or spicy foods that sting your mouth; or very hot or cold food. A dietitian can suggest ways to modify the texture of foods so they are easier to swallow.
  • Avoid smoking, drinking alcohol or caffeinated drinks, and consuming citrus or tangy tomato-based food and juice, as they will irritate your mouth and make dryness worse.
  • If chewing and swallowing are painful, try to have more liquids or soft food. Talk to a dietitian, who can suggest nourishing foods that will not hurt your mouth.
  • If you have trouble swallowing, ask your doctor for a referral to a speech pathologist.
  • To manage taste changes, try different ways of preparing food. For example, add lemon juice to meat and vegetables, marinate foods or add herbs.
  • Talk to your doctor if eating is uncomfortable or difficult. If you are in pain, pain medicine may help with swallowing.
  • Rinse your mouth regularly using an alcohol-free mouthwash recommended by your doctor or dentist.
  • Saltwater is a natural disinfectant – you can make a saltwater mouthwash at home by dissolving ¼ teaspoon of salt into 1 cup of warm water. Rinse your mouth with plain water afterwards.

Swallowing and taste changes

You may have thick phlegm in your throat, or a lump-like feeling that makes it hard to swallow. Food may also taste different. Taste changes may last for many months after treatment, but normal taste usually returns eventually. Sometimes, swallowing may be affected for months after treatment and your speech pathologist will monitor you closely to help you recover. Rarely, swallowing problems may be permanent.

Download our fact sheet ‘Mouth health and cancer treatment’

Download our fact sheet ‘Understanding Taste and Smell Changes’

To reduce the effects of radiation on the bowel, the radiation therapists may advise you to drink fluids before each session so you have a full bladder. This will expand your bladder and push the bowel higher up into the abdomen, away from the radiation.

Even with precautions, radiation therapy can irritate the lining of the bowel or stomach. These changes are usually temporary, but for some people they are permanent and can have a significant impact on quality of life. It is important to talk to your treatment team if you are finding bowel issues difficult to manage.

Diarrhoea – This is when you have frequent loose, watery bowel motions. You will need to go to the toilet more urgently and more often. You may also get abdominal cramping, excess wind and pain. Having diarrhoea can be tiring, so rest as much as possible. Diarrhoea can take some weeks to settle down after treatment has finished.

Radiation proctitis – Radiation therapy to the pelvic area can damage the lining of the rectum, causing inflammation and swelling known as radiation proctitis. This can cause a range of symptoms including blood and mucus in bowel motions; discomfort opening the bowels; or the need to empty the bowels often, perhaps with little result. Talk to your treatment team about your risk of developing radiation proctitis. If you have any ongoing bowel problems, they may refer you to a gastroenterologist.

How to manage bowel problems

  • Your doctor may prescribe medicines to relieve symptoms of diarrhoea. Check with your treatment team before taking any over-the-counter or home remedies, as taking them with anti-diarrhoea medicines may cause unwanted effects.
  • Drink peppermint or chamomile tea to reduce abdominal or wind pain.
  • Eat or drink as well as you can so your body gets the energy and nutrients it needs.
  • Do some gentle exercise, such as walking, to encourage healthy bowel movements.
  • Drink lots of clear liquids when you first notice symptoms of diarrhoea. This helps to avoid dehydration. Try apple juice, weak tea and clear broth.
  • If you have diarrhoea, avoid fatty, spicy or fried foods, and rich gravies and sauces. Choose plain foods that are low in insoluble fibre (e.g. bananas, mashed potato, white rice, steamed white fish). Talk to your dietitian about what else you can eat.
  • Contact your treatment team immediately if there is blood in your bowel motions or if you have more than 5–6 bowel movements in 24 hours.

The blood vessels in the bowel can become more fragile after radiation therapy. This can cause blood to appear in your bowel movements, even months or years after treatment. Always let your doctor know if you notice new or unusual bleeding.

Radiation therapy to the abdomen or pelvic area can irritate the bladder or, more often, the urethra (the tube that carries urine from the bladder to the outside of the body).

Cystitis – You may feel you want to pass urine more often or you might have some stinging when you pass urine. This is called cystitis. Try to drink plenty of water to make your urine less concentrated.

Urinary incontinence – Incontinence is when urine leaks from your bladder without your control. After radiation therapy, you may need to pass urine more often, particularly at night, or feel as if you need to go in a hurry. You may leak a few drops of urine when you cough, sneeze, laugh or strain. Strengthening the pelvic floor muscles can help with bladder control. Ask your doctor for a referral to a continence nurse or physiotherapist, or contact the National Continence Helpline on 1800 33 00 66 or at

Let your treatment team know if you have bladder or urinary problems, as they will be able to suggest strategies and may recommend medicines. To help manage these side effects, drink plenty of fluids and avoid drinking strong coffee, tea and alcohol.

The blood vessels in the bladder can become more fragile after radiation therapy. This can cause blood to appear in your urine even months or years after treatment. Always let your doctor know if you notice new or unusual bleeding.

Lymphoedema is swelling that occurs in soft tissue. If lymph nodes or lymph vessels have been damaged during radiation therapy, lymph fluid may not drain properly. If lymph fluid builds up, it can cause swelling in the area being treated. Lymphoedema usually occurs in an arm or leg, but can also affect other parts of the body.

People who have had surgery followed by radiation therapy are more at risk. Lymphoedema or swelling is sometimes just a temporary effect of radiation therapy, but it can be ongoing. It can also be a late effect, appearing months or even years after treatment.

Lymphoedema is easier to manage if the condition is treated early. The main signs of lymphoedema include swelling, redness and skin warmth, which may come and go. It is important to avoid pressure, injury or infection to the affected part of your body, and to see your doctor if you have any signs of lymphoedema.

Some hospitals have specialist physiotherapists who can teach you simple exercises to reduce your risk of developing lymphoedema or show you ways to manage it if you have developed it. There are also outpatient and private lymphoedema practitioners.

Lymphoedema practitioners can develop a personalised treatment program. This may include exercises, skin care, lymphatic drainage massage and compression garments, if needed. To find a lymphoedema practitioner, visit the Australasian Lymphology Association.

Radiation therapy can affect your sexuality and fertility in emotional and physical ways. These changes are common. Some changes may be only temporary while others may be permanent.

Changes in sexuality

You may notice a lack of interest in sex or a loss of desire (libido). Or you may feel too tired or sick to want to be intimate. Some people may feel less sexually attractive to their partner because of changes to their body. All of these feelings are quite common. Radiation therapy can also make sexual intercourse uncomfortable, depending on where the radiation therapy is given. Talk to your doctor about ways to manage side effects that change your sex life.

Using contraception

A woman’s eggs (ova) and a man’s sperm can be affected by very small amounts of radiation when having radiation therapy to any part of the body. Depending on the type of treatment you have, your doctor may talk to you about using a barrier method of contraception (such as a condom or female condom). If pregnancy is possible, your doctor will advise you to avoid pregnancy by using contraception during radiation therapy and for at least six months after you have finished treatment. Talk to your doctor as soon as possible if pregnancy occurs.

Changes in fertility

Radiation therapy to the pelvis, abdomen and sexual organs can temporarily or permanently affect your ability to have children (fertility). Radiation therapy to the brain can affect the pituitary gland, which controls the hormones the body needs to produce eggs or sperm.

If infertility is a potential side effect, your radiation oncologist will discuss it with you before treatment starts. Let them know if you think you may want to have children in future. Ask what can be done to reduce the chance of problems and whether you should see a fertility specialist beforehand. Sometimes, however, it is not possible to properly treat the cancer and maintain fertility.

Many people experience a sense of loss when they learn they may no longer be able to have children. If you have a partner, talk to them about your feelings. Talking to a counsellor may also help.

Effects on fertility and sexual function

Radiation therapy to the abdomen, pelvis and reproductive organs can affect your sexual function and ability to have children.

Changes to the vagina

  • Radiation therapy to the vulva or vagina may cause inflammation, making intercourse painful. This usually improves in the weeks after treatment ends. Your treatment team will recommend creams and pain relief to use until the skin heals.
  • The vagina may become shorter and narrower (vaginal stenosis), which may make intercourse difficult or painful. Having regular intercourse or using vaginal dilators after treatment ends can help keep the vagina open. Wait until any soreness or inflammation has settled before you start using a dilator or having sexual intercourse. This is usually 2–6 weeks after your last session of radiation therapy. Using a dilator can be challenging. Your doctor or a physiotherapist can provide instructions.
  • Talk to your doctor about vaginal moisturisers or oestrogen creams, which may help with vaginal discomfort.
  • If sexual penetration is painful or difficult, explore different ways to orgasm or climax.


  • Radiation therapy to the pelvic area or abdomen usually stops the ovaries producing female hormones, which leads to early menopause.
  • Your periods will stop and you may have menopausal symptoms. These may include hot flushes, dry skin, vaginal dryness, mood swings, trouble sleeping (insomnia) and tiredness.
  • If vaginal dryness is a problem, take more time before and during sex to give yourself time to become aroused. Extra lubrication may make intercourse more comfortable.
  • Discuss changes to your libido with your partner so they understand how you’re feeling.
  • Talk to your doctor about ways to manage the symptoms of menopause. If you need more support resuming sexual activity, ask your doctor for a referral to a sexual therapist or psychologist.

Sperm production and erection problems

  • Radiation therapy to the pelvic area or near the testicles may temporarily reduce sperm production. You may feel the sensations of orgasm, but
    ejaculate little or no semen. This is called a dry orgasm. Semen production often returns to normal after a few months.
  • Depending on the dose and the area of the pelvis treated, you may have problems getting and maintaining erections, and ejaculation may be painful for a few weeks after treatment. For some men, the difficulty with erections may be permanent.
  • Talk to your treatment team if these effects are ongoing and causing you distress. They can suggest ways to manage them, such as prescription
    medicines, penile implants or vacuum erection devices.


  • For some men, the effect on sperm production and ability to have erections is permanent and causes infertility. If you want to father a child, you may wish to store sperm before treatment starts so your partner can conceive through artificial insemination or in-vitro fertilisation in the future.
  • If radiation therapy causes menopause, you will no longer be able to become pregnant. If you wish to have children in the future, talk to your  radiation oncologist before treatment starts about ways to preserve your fertility, such as storing eggs or embryos.
  • If your ovaries don’t need to be treated, one or both of the ovaries may be surgically moved higher in the abdomen and out of the field of radiation. This is called ovarian transposition or relocation (oophoropexy), and it may help the ovaries keep working properly.

Download our booklet ‘Sexuality, Intimacy and Cancer’

Download our booklet ‘Fertility and Cancer’

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Understanding Radiation Therapy

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