Side effects

No matter which area of your body is being treated, it is likely that you will experience some side effects. Your side effects will depend on:

  • the amount of radiation you are given
  • the area of your body being treated
  • your individual response
  • the type of radiation you receive
  • other treatments you are having (for example chemotherapy).

Acute side effects are caused by the inflammation created by radiation beams passing through normal tissue. These side effects develop during the course of treatment, and are most noticeable a week to ten days after your treatment has finished. Most side effects will be greatly reduced around four to six weeks after the treatment has finished.

“I felt great for the first few weeks, but when I started to notice side effects in my second-to-last week, it was good to know this was normal.” Jiao Jiao

Chronic or late side effects may develop many months and sometimes years later.

Your treatment will be carefully planned to minimise both acute and chronic side effects, but some side effects are still possible. Your radiation treatment team will tell you what you may experience before you start treatment. If you are concerned about the side effects of your treatment, you can ask questions at any time.

Ka ata maheretia tō maimoatanga ki te whakaiti i ngā pānga tārūrū me ngā pānga mau tonu ki te taha, engari, tērā pea ka puta tonu he pānga ki te taha. Mā tō rōpū maimoatanga iraruke koe e kōrero mō ngā āhuatanga ka pā ki a koe i mua i tō tīmata i te maimoa. Mehemea kei te āwangawanga koe mō ngā pānga ki te taha i te wā o tō maimoatanga, e āhei ana koe ki te whakatakoto pātai, ahakoa te wā

Feeling tired or fatigued

Most people having radiation treatment will experience tiredness or fatigue during their treatment. This can be caused by a number of factors:

  • the radiation treatment and its side effects
  • other treatments you may be having
  • traveling to and from the hospital each day
  • changes to your routine
  • anxiety about treatment.

You may need to take time off work during and after your treatment. If this is going to be a problem for you, your radiation treatment team can refer you to a social worker. If you are having difficulty sleeping, let your radiation treatment team know.

Tips for coping with tiredness and fatigue:

  • ask friends and family/whānau for help with chores and preparing meals
  • take regular rests
  • regular, gentle exercise is known to help
  • let your treatment team know if you are not managing at home as there may be help available
  • relaxation techniques can be helpful.

The Cancer Society information sheet If you’re having difficulty sleeping 


Effects on your skin

Skin in the treatment area might become dry, flaky, red, itchy or sore – similar to sunburn. If you are unsure which parts of your skin will be affected, ask your radiation treatment team.

Your skin might also be more sensitive than usual to the sun and changes in temperature. Once your skin has healed, it is recommended that you keep the area out of the sun and ask your doctor about using sunscreen (at least SPF 30).

It is also recommended that you do not go into a swimming pool during your treatment, as you are likely to develop a skin reaction.

If you have a skin reaction, it will usually settle down four to six weeks after your treatment has finished. The treated area may be slightly darker than the surrounding skin.

Your radiation treatment team will teach you how to look after your skin during your treatment.

Only use products on your skin that have been recommended by your radiation treatment team.

Me whakamahi anake koe i ngā panipani mō tō kiri kua tūtohutia e tō rōpū maimoa iraruke.



Some people experience some pain or discomfort during radiation treatment. This can often be well managed with medication prescribed by a doctor. Read our information on managing pain here.


Hair loss

You may lose some or all of the hair on the part of your body that is being treated, for example the scalp, chest, pubic area or face. This might be temporary or permanent. If you have lost or are losing hair from your head, you could consider wearing a wig, hairpiece, hat, turban or scarf.

If you decide to wear a hairpiece or wig, it is a good idea to get one fitted before you start losing your hair, so that it matches your style and colour as closely as possible. The Ministry of Health can help to pay the cost of a hairpiece, wig or head covering. Ask your doctor for a certificate that states your entitlement.

For more information, see the Cancer Society’s information sheet Coping with hair loss.


Not wanting to eat

During radiation treatment you may notice changes to your appetite. Your sense of taste might also change, especially if you have radiation treatment to your head and neck. Please let your radiation treatment team know if you do not feel like eating, are losing weight or are having difficulty eating or swallowing food. They can recommend ways to make this easier for you. This may involve seeing a dietician.

For more information, see the Cancer Society’s booklet Eating Well During Cancer Treatment/Kia Pai te Kai te wā Maimoatanga Matepukupuku on our website


Feeling sick and vomiting

You may feel sick if you are having radiation to the oesophagus (food tube), stomach, bowel, brain or pelvic area. Make sure you tell your radiation treatment team if you are feeling sick or vomiting. Your radiation oncologist can prescribe medication to help relieve these side effects.

Tips to help if you are feeling sick:

  • avoid food with strong smells, or have it cold
  • avoid food that is fatty, fried, spicy or very sweet
  • eat small meals often rather than three large meals, as an empty stomach can make you feel sicker
  • some people find that ginger and peppermint help
  • drink plenty of fluids – having small amounts regularly may be easier to manage.

Tips to help if you have been sick:

  • try taking small sips of fluids or suck on an ice cube
  • try to eat something plain like crackers or dry toast
  • if you continue to feel sick, let your radiation treatment team know.


Bowel problems

During radiation treatment to the pelvic area, the large bowel (colon and rectum) and anus can become inflamed. You might find that you have some of the following symptoms:

  • diarrhoea or loose stools
  • needing to rush to the toilet, or leaking from your bowel
  • feeling that your bowel has not emptied properly
  • passing lots of wind
  • passing blood from your bowel.

It is important to let your radiation treatment team know if you are experiencing any of these side effects.

Once radiation treatment has ended, the inflammation usually settles down over a few weeks or months. You may be left with long-term bowel changes.


Bladder problems

During radiation treatment to the pelvic area, you may experience some of the following bladder problems:

  • needing to pass urine often (frequency)
  • a burning sensation when you urinate
  • feeling that you cannot wait when you need to empty your bladder (urgency)
  • blood in your urine (haematuria)
  • a weak flow of urine and your bladder not emptying completely
  • needing to get up at night to urinate.

Less common symptoms include:

  • a small amount of urine leaking (incontinence) – especially when you laugh, sneeze or cough
  • pain when urinating
  • passing blood clots
  • difficulty passing urine.

It is important to let your radiation treatment team know if you are experiencing any of these side effects so that they can help you to manage them.


Mouth and throat problems

The lining of your mouth will react to radiation treatment. It may become sore, red and ulcerated, and you may develop a dry mouth and taste changes.

A sore mouth and throat

Let your radiation treatment team know if you have a sore or dry mouth. A dietician and speech language therapist may see you during your treatment.

“I did get a few ulcers in the back there, though spicy foods didn’t set it off. It was strawberries and berries that did it.” Melinda

Tips to help:

  • try to drink nutritious liquids such as milkshakes and smoothies
  • let food and drink cool down before you eat/drink them
  • if it is painful to chew or swallow, choose softer foods such as soup, yoghurt and porridge
  • if you have a dry mouth, gravies and sauces will help you to chew and swallow food
  • take pain relief as prescribed
  • avoid smoking and alcohol
  • avoid spicy foods such as chilli and curry
  • avoid acidic foods such as kiwifruit, tomatoes and berries
  • avoid foods with a rough texture, such as toast, chips and pastry.

For more information, see the Cancer Society’s information sheet on coping with mouth problems.


Dry mouth

Saliva helps to protect your teeth from decay and helps you to eat. A dry mouth is caused by damage to the salivary glands from radiation treatment, and it can be permanent. This is most likely to occur when you are having radiation to your head and neck.

Tips to help manage a dry mouth:

  • drink water often, carrying a water bottle with you can help you to remember to drink
  • chewing sugar-free gum may help saliva flow
  • there are products available to keep your mouth moist, speak to your radiation treatment team about these products and where to purchase them
  • there are products that help to prevent dental decay and you will need to keep using them if your mouth is dry
  • only use recommended mouthwashes
  • you will need to have dental check-ups more often if your mouth is dry.

For more information, see the Cancer Society’s booklet Living with Dry Mouth/Te Noho me te Waha Maroke on our website

Taste changes

Taste changes are caused by damage to your taste buds from radiation treatment, and the changes are usually temporary. This may mean you need to try different foods while you are having your treatment. Taste usually begins to recover several weeks after treatment finishes, but it may take many months to return, or it may be permanently changed.

If you are having radiation treatment to your mouth, your teeth will be more likely to decay. Discuss dental care with your doctor and dentist before your treatment starts, so that any dental work can be arranged before your radiation treatment begins.

For more information, see the Cancer Society’s information sheet Taste changes and chemotherapy and radiation treatment on our website


Effects on your pelvic area

Radiation treatment to the pelvic area in women can cause inflammation of the walls of the vagina. When inflammation reduces, scar tissue can form, which can make the vagina narrower and shorter. The vaginal walls might be dry and thin and can stick together. Less vaginal lubricant may be produced.

This can have three effects:

  • make you more likely to get vaginal infections such as thrush
  • make pelvic examinations uncomfortable
  • make having vaginal intercourse painful and difficult.

To prevent scar tissue forming, you may be advised to use vaginal 36 dilators. Vaginal dilators are tampon-shaped plastic devices with rounded ends. There are a number of types available, and they come in varying sizes. You can also use a vibrator or your fingers to gently stretch the vagina to keep it supple. Instructions for using dilators/ vibrators will be given to you by your radiation treatment team.

Regular sex can also help to keep the vagina healthy, but this may be uncomfortable at first. Positions where you are more in control of the pace and depth of penetration may be more comfortable. Ask your doctor or radiation treatment team for more information.

Men who undergo radiation treatment to the pelvis might experience erection problems and have less desire to have sex. This can be distressing, and may be a long-term side effect of radiation treatment. Talk to your radiation oncologist, as sometimes erection problems are permanent.

“Through the treatment I lost all my sex drive. It’s a real downer. Luckily I can talk to my partner about this.” Brent

Anal penetration may not be recommended during treatment to your pelvis, as your anus and rectum may also be affected by the treatment.

Ongoing concerns with intimacy, sex and sexual relationships

Talk to someone you trust if you are experiencing difficulties or ongoing concerns with intimacy and/or sexual relationships. Friends, family/whānau members, radiation therapists, nurses or your doctor may be able to help.

Your local Cancer Society can also provide information about sexual counselling services.

You may also wish to read our booklet Sex and Cancer, which is available on our website



If you are having pelvic radiation and/or some chemotherapy combinations, you might become infertile either temporarily or permanently. Talk to your doctor about this before you start treatment.

Contraception during and after radiation treatment

While you are having radiation treatment you will need to use a reliable form of birth control. It is important that neither you nor your partner becomes pregnant, as radiation treatment may harm a developing baby. If you are pregnant now, talk to your doctor immediately.


Side effects of skin cancer treatment

Radiation treatment affects only the skin in the area being treated and it will not make you feel unwell. For a few weeks after treatment the treated skin will be red and inflamed. During this time it will look as though the treatment has made things worse rather than better. Try not to worry about this. After a few weeks the area will dry up and form a crust or scab. In another week or so the scab will peel away, leaving new skin underneath. It is important to not pick at the scab. At first the new skin will look pinker than the skin around it.

For some patients, the skin will have a tan in the area where radiation was given. This will gradually fade, and the treated area will look like the skin around it.



If you have radiation treatment to or near your lymph nodes, you will have an increased risk of developing lymphoedema.

Lymphoedema is a swelling of one or more parts of the body, caused by a build-up of lymph fluid in the surface tissues of the body. It can happen as a result of damage to the lymphatic system (for example, because of radiation treatment and/or surgery to an area of lymph nodes in the body). If this happens for you, talk to your doctor or nurse about ways to manage it.

For more information, see the Cancer Society’s information sheets Understanding lymphoedema and Living with lymphoedema