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Macmillan and Cancerbackup merged in 2008. Together we provide free, high quality information for people affected by cancer through our publications, website and phone service. Find out more| .
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This section gives information about the side effects of external radiotherapy| to different areas of the body. As radiotherapy treats only the part of the body affected by the cancer, you only need to read the section that relates to your treatment area. See the cancer type section for more information about how radiotherapy is given for specific cancers.
Your mouth may become sore during treatment because the cells that line the mouth are very sensitive to radiation. This can happen after 2–3 weeks of radiotherapy and may be more severe if you are having chemotherapy| as well. The treatment may also make you more likely to develop mouth infections such as thrush, and you may find that you are producing sticky mucus.
It's very important to take care of your mouth while you are having treatment; the radiotherapy staff or a dental hygienist will show you how to do this. Regular mouthwashes, lozenges and painkillers will be prescribed for you when necessary.
As your mouth will be more sensitive than usual, try to avoid hot, spicy or very cold food or drink. Also avoid hard foods such as toast. Use only the mouthwashes prescribed for you by the radiotherapy department, as mouthwashes bought from a shop or chemist are usually alcohol-based and can make the soreness worse.
Your taste buds may be affected by treatment and you may notice changes in the way your food tastes. Some people say food has a metallic taste, while others say that all foods taste the same. As the effects of the treatment fade away your sense of taste will probably return to normal, but it may take over a year for this to happen. The radiotherapy staff can arrange for you to talk to a dietitian for advice on adapting your diet to overcome any taste changes.
Alcohol (particularly spirits) and tobacco can irritate the lining of the mouth and it’s best to avoid them during your treatment and for a few weeks afterwards. Your specialist may advise you to stop altogether if you can.
The glands that produce saliva may be affected by the treatment, making you produce less saliva or none at all. This can make it uncomfortable to chew or swallow. The dryness in your mouth| may last for several months after treatment and for some people it may be permanent. These side effects can be difficult to cope with at first, but there are ways to help. Your specialist can prescribe different treatments to help keep your mouth moist.
The above side effects in your mouth may cause a loss of appetite and weight loss. Food supplements, such as high-calorie drinks, will be recommended until your mouth feels better. If you are having problems with eating, talk to your radiographers or the nursing staff, who will be able to help. You may be referred to a dietitian for specific advice. Our section on eating well| also has some useful tips.
If eating and drinking become too painful, a thin, flexible tube, called a nasogastric (NG) tube|, may be passed up your nose and down into your stomach. Liquid foods can be given through the NG tube. Another way of giving liquid foods is by passing a tube (a PEG or RIG tube|) through the wall of your abdomen and into the stomach. This can be done while you are under general anaesthetic, usually when you are having surgery for the cancer. Being fed for a time through a feeding tube may be the best way to make sure you keep up your strength during your treatment.
If you are having treatment to your voice box (larynx)|, you may notice that your voice becomes hoarse or husky and may disappear completely at times. These changes are only temporary and it should go back to normal a few weeks after your treatment is over.
Radiotherapy to the mouth can make you more likely to get tooth decay and you will need more frequent check-ups at the dentist. Fluoride treatment can often help to protect your teeth against the effects of radiotherapy, and your clinical oncologist may refer you for special dental treatment before your radiotherapy starts.
Gently brushing your teeth with a soft toothbrush and high-fluoride toothpaste as many as five or six times a day will help. It is important to tell your dentist that you have had radiotherapy before having any dental work later on.
About two to three weeks (but sometimes only a few days) after radiotherapy to the chest has started, you might notice that your chest feels tight, which makes it difficult to swallow solid foods.This is a common reaction to treatment. It may help to try a soft, plain diet supplemented by high-calorie drinks such as Build-Up® and Complan®. By trying different foods, you’ll find out which ones are easiest to swallow. Your specialist may prescribe painkillers or liquid medicines (such as Asilone®, Maalox® or Altacite Plus®) to be taken before meals to make eating less uncomfortable. The discomfort will usually get better on its own in about five to eight weeks.
Some people find that their treatment makes them feel sick (nauseated), and sometimes they may actually be sick (vomit). This is most common when the treatment area is near the stomach. Your specialist can prescribe anti-sickness drugs (anti-emetics) if this happens, and may prescribe them anyway, as a precaution. They are usually very effective.
Tell your specialist if you have any nausea or vomiting|, and remember that it usually stops once treatment is over.
If you are having problems with eating or sickness, you may begin to lose weight. This can make you feel tired and weak. At times you may not feel like eating. The dietitian or your specialist will be able to give you advice if eating is a problem, and our section on eating well| gives helpful advice on dealing with this.
After radiotherapy to the chest you may notice that you develop a dry cough and breathlessness|. This side effect may not occur until several months after your treatment. Whenever it happens you should report it to your doctor, who may treat it with a course of steroids and possibly antibiotics.
It is important to let your doctor know if you notice any changes in your breathing at any time during and after your treatment.
This is a fairly common side effect of treatment to this area, and stomach cramps and wind may also occur. As well as being unpleasant, diarrhoea| can make you feel weak and tired. Your specialist can prescribe anti-diarrhoea drugs for you. If a large area of the abdomen or pelvis is being treated, you may be advised to drink lots of fluid. You will generally be advised to eat a normal healthy diet|. The diarrhoea may continue for some weeks after your treatment. If it doesn't seem to be getting better over time, contact the radiotherapy department or your doctor.
Your rectum (back passage) may become irritated by the radiotherapy if the area being treated is in the lower pelvis; such as radiotherapy for womb|, prostate, rectal| or bladder cancer|. If this is likely you may be advised to follow a high-fibre diet to avoid becoming constipated, as constipation can make the irritation of the back passage (proctitis) worse.
If you already have piles, they may become more irritating, and local anaesthetic, steroid creams or suppositories may be prescribed to ease any discomfort. Sometimes, after radiotherapy to the pelvic area, there may be a mucus discharge or some bleeding from the back passage. Let your specialist know if you have any of these problems.
Some people find that their treatment makes them feel sick (nauseated) and they may actually be sick (vomit). Your specialist can prescribe anti-sickness drugs (anti-emetics)| for you. Any feeling of sickness usually stops once your treatment is over.
These side effects may occur as a result of diarrhoea and nausea. At times you may not feel like eating, and the idea of preparing food may make you feel sick. If you can, ask someone else to prepare your meals for you. You may find it easier to eat little and often – having small, more frequent meals or snacks rather than conventional larger meals at set times.
Food supplements|, such as Build-Up® and Complan®, can be used in place of meals to add necessary calories. Your dietitian or specialist can give you advice if eating becomes a problem for you.
Our section on eating well| may be helpful. Occasionally, if you continue to lose weight, you may need to spend a short time in hospital so that you can be fed in other ways. Liquid food can be given into a vein (intravenously) or by a tube through your nose and into your stomach (a nasogastric or NG tube|) until you are able to eat properly again.
Inflammation of the bladder (cystitis) may develop during radiotherapy to the lower abdomen, usually after several treatments have been given. You may notice a burning sensation or discomfort when you pass urine, and feel that you need to pass water more often than usual, including during the night.
Drinking more fluids will help to relieve these symptoms, but try to avoid coffee, tea, alcohol and acidic fruit juices such as orange juice, as these irritate the bladder and will make the symptoms worse. Some people find that cranberry juice or lemon barley water help to reduce the symptoms. If necessary, medicines can be given to treat these symptoms.
See our detailed information about how to cope with the side effects of pelvic radiotherapy in women| and men|.
Also see the effects of pelvic radiotherapy on fertility| and sexuality|.
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