What are the possible side effects?

Side effects of radiation therapy depend on:

• the amount of radiation given
• the area of the body treated
• the individual response.

Side effects are commonly grouped into those that develop early on, during or at the end of the treatment (the acute side effects) and those that develop many months if not years later (late side effects).

Acute side effects are caused by radiation to those normal tissues in the body that are in the path of the radiation. This radiation results in inflammation of those tissues. These effects build up during the course of the treatment. Most side effects will be much improved by about six weeks after the treatment has finished. Your doctor will tell you what you are likely to experience.

Late side effects appear many months or years later. The inflammation of the tissues will have been healed by the body. Sometimes the initial damage and this healing process might result in scarring and damage to the blood supply to some tissues, which will restrict the function of those tissues. Your treatment will have been planned specifically to minimise the likelihood of late complications and any significant risks that might exist will be discussed with you by your doctor.

Feeling tired

Fatigue/tiredness is a major side effect of radiation therapy. If you do get tired try to take things easier. Only do as much as you feel comfortable doing. Try to plan rest times in your day. Also try to ensure you are drinking plenty of fluids, eating well and having some form of physical activity. This will help you cope better with the treatment.

If you're not sleeping well, tell your doctor or nurse. They may be able to suggest ways to help, or prescribe sleeping tablets or a mild relaxant.

Effects on the skin

• The skin in the treatment area may become dry, flaky, red, itchy or sore, similar to sunburn.
• Your skin may also be more sensitive than usual to the sun, so try to keep treated areas out of the sun during and after treatment. Ask your doctor about using a sunscreen (SPF 30+).
• Wear soft, loose clothing.
• Tell your doctor about changes in your skin, such as cracks, blisters, very moist skin, rashes, infections or peeling, or any changes in your nails.
• Don't rub, scrub or scratch treated skin or any sensitive spots.
• Follow skin care advice given by your treatment team, eg, avoid using soap, perfume, deodorant; use a soft towel; bath or shower in lukewarm water.
• Do not put hot-water bottles or ice packs on treated areas.
• If skin becomes sore, only use products recommended by the treatment team.

Hair loss

You may lose some or all of your hair in the treatment area, eg.  scalp, chest, face. This may be permanent or temporary. 

If you have lost, or are losing, your hair you could consider wearing a wig, hair piece or a stylish hat or scarf for a while. If you decide to wear a hair piece or wig, it’s a good idea to get one fitted before you start losing your hair, so that it matches as closely as possible your style and colour. The Government helps pay the cost of a hair piece or wig. Ask your doctor for a certificate that states your entitlement.

Not wanting to eat

You may have no problems with your appetite during treatment, or you may not feel like eating at all. Your sense of taste may change. This change can last for the duration of the treatment but will then return to normal once it stops.

Do try to eat as well as possible during your treatment to maintain your energy levels and avoid weight loss. If you don't feel like eating, try different foods until you find foods that you want to eat. Eat smaller amounts more often, or try drinking special liquid supplement foods that you can get from your pharmacist. Even when you are unable to eat very much it is important to drink plenty of clear fluids.

Your hospital may have its own diet information for cancer patients.  You can also talk to the hospital or community dietitian for advice about what to eat.

Feeling sick and diarrhoea

Feeling sick, vomiting and diarrhoea may happen if you are having radiation to the stomach or pelvic area. Your radiation oncologist can prescribe medication to help relieve these symptoms.

Mouth and throat problems

Radiation therapy can give you a sore or dry mouth or throat and your voice may become hoarse.
If your mouth or throat is dry and you have trouble swallowing, try some of these ideas:

• suck on ice blocks
• drink lots of liquids
• moisten foods with butter
• dunk dry biscuits in tea
• blend foods and eat soups and ice creams
• ask your dentist, doctor or nurse about artificial saliva
• don't smoke or drink alcohol.

If you are having radiation therapy to your mouth, your teeth will be more likely to decay. If possible, discuss dental care with your doctor before your treatment starts, and tell your dentist about your treatment, so that the doctor and dentist can discuss any dental work you need before your radiation therapy begins.

Support during treatment

During treatment the radiation oncologist will see you every 1-2 weeks to help you with any problems. You can also speak to one of the radiation therapists or nurses if you have any concerns.

Related topics

What is radiation therapy? See Radiation therapy

What about food and cancer treatment? For advice about your diet, see Eating well when you have cancer

What about sex if you have cancer? For information on how sexual practices may be affected, see Cancer and sex

Original material provided by the Cancer Society of New Zealand, 2005. Reviewed by everybody, September 2008.