Radiotherapy treats cancer by using high-energy rays to destroy the cancer cells in one area of the body, while doing as little harm as possible to normal cells. The treatment is usually given in the hospital radiotherapy department as a series of short daily sessions over a few weeks.

The treatments are usually given from Monday to Friday, with a rest at the weekend. Each treatment takes about 10–15 minutes. Your doctor will discuss the treatment and possible side effects with you. How long treatment is given for depends on the type of tumour.

Radiotherapy has to be planned carefully and this may take a few visits. On your child’s first visit to the radiotherapy department, they may have a CT scan or lie under a machine called a simulator. The CT scanner or simulator takes x-rays of the area to be treated. The treatment is planned by a cancer specialist (clinical oncologist). Marks may be drawn on your child’s skin to help the radiographer (who gives their treatment) to position them accurately. This makes sure that the treatment is given to exactly the right place each time.

Sometimes your child may have a clear plastic mould made to keep the affected part of the body still each time the treatment is given. If this is necessary, the doctor or specialist nurse will explain the process to you.

At the beginning of each session of radiotherapy, the radiographer will position your child carefully on the couch, and make sure they are comfortable. During the treatment, your child will be left alone in the room but they will be able to talk to the radiographer, who will be watching from the next room. You can be with the radiographer, so you can see your child and talk with them. Often, story tapes can be played, or you can read stories over the communication system.

Radiotherapy is not painful but your child has to lie completely still for a few minutes while the treatment is being given. With young children, or if children are not able to keep still, they may be given a sedative. Occasionally they may need to have a short general anaesthetic to allow the treatment to be given.

The immediate side effects of radiotherapy are usually very mild.

Tiredness

Your child may feel very tired while they are having the treatment and for a few weeks afterwards. Their energy levels may take a few months to get back to normal once the treatment is finished.

Loss of appetite

You may find that your child loses their appetite. It may help for them to have frequent small snacks throughout the day, rather than large meals.

Effect on bone marrow

Radiotherapy to some parts of the body can sometimes affect the bone marrow, which produces the different types of blood cells. If this is thought likely in your child’s case they will have regular blood tests during their treatment, to check their blood cell levels. If these are low, they may feel very tired and lethargic.

Effects on skin

Some children develop a skin reaction, similar to sunburn, while having radiotherapy. This may happen after 3–4 weeks. In children with pale skin, the skin in the treatment area can become red and sore or itchy. In those with dark skin, it becomes darker. The amount of the reaction depends on the area being treated and the individual child’s skin type. Some children have no skin problems at all. Your child’s radiographers will be looking for these reactions but you should also let them know as soon as you see any soreness.

Long-term side effects

Radiotherapy can cause some other longer-term side effects, which will start gradually, months or sometimes years after the treatment. As time goes by, the effect of radiotherapy to any growing tissues may become more noticeable. In particular, radiotherapy to the brain can affect growth and development. Your doctor will be able to discuss this with you in detail.

Our radiotherapy section gives more information about radiotherapy and how to deal with any side effects.

As well as the possible general side effects, a child having radiotherapy treatment to the abdomen and pelvis may develop any of the following side effects.

Diarrhoea

Diarrhoea is a fairly common side effect of treatment to the abdomen. Your child may also have stomach cramps and a windy tummy. Your child’s specialist can prescribe medicines to control diarrhoea. It is important that your child drinks lots of fluid. The diarrhoea may continue for some weeks after the treatment. As well as being unpleasant, diarrhoea can make your child feel weak and tired. If it continues, and doesn’t seem to be getting any better, contact the radiotherapy department or your child’s doctor for further advice.

Soreness around the back passage

The skin around the back passage (anus) may become irritated by the radiotherapy, if the area being treated is in the lower pelvis. Sometimes, after radiotherapy to the pelvic area, there may be a mucous-like discharge, or bleeding, from the back passage. Let your specialist know if your child has any of these problems.

Feeling sick

Some children feel sick (nauseous), and sometimes they may actually be sick (vomit), during radiotherapy treatment to the abdomen or pelvis. Tell your specialist if your child experiences any nausea or vomiting as they can prescribe anti-sickness drugs (anti-emetics). These drugs are usually very successful. Any feeling of sickness usually stops once treatment is over.

Poor appetite and weight loss

These may occur as a result of diarrhoea and nausea. At times, your child may not feel like eating. They may find it easier to eat little and often, having small, more frequent meals or snacks, rather than larger meals at set times. High-calorie drinks (which your doctor can prescribe) can be used in place of meals. If eating becomes a problem for your child, the dietitian or your specialist can advise you about nutritional supplements.

Occasionally, if your child continues to lose weight, it may be necessary for them to spend a short time in hospital so that they can be fed in special ways: liquid food can be given through a central line, which is inserted into a vein in their chest, or by a tube passed through their nose and into their stomach (a naso-gastric or NG tube), until they are able to eat properly again. Staff can explain what this involves, and will include you in decisions about the best way to feed your child.

Pain while passing urine

The bladder can become inflamed (cystitis) if radiotherapy is given to the pelvic area (usually after several treatments have been given). Your child may tell you that it ‘burns’ or ‘stings’, or is sore when they pass urine. You might notice that they need to pee more than usual. It is important that your child drinks plenty of fluids as this can help to ease the discomfort.

Some children find that drinking cranberry juice or lemon barley water helps to reduce symptoms. If necessary, medicines may be given. Your child may also have their urine checked regularly to make sure that they do not have an infection.

Infertility

Radiotherapy given directly to the ovaries (where eggs are stored) or testicles (where sperm is made) is very likely to cause infertility. Radiotherapy to parts of the body near the testicles and ovaries, including the lower parts of the spine, may also have an effect. However, boys who have reached puberty may be able to bank sperm before treatment.

If radiotherapy is given to the womb or a nearby area, this can affect fertility. For example, it can make it more difficult for the womb to support a growing baby during pregnancy. There may be a higher risk of miscarriage, or the baby may be born small, or prematurely.

It can be very distressing to think that your child may not be able to have children in the future. Your child may also find this difficult to cope with, either now or in the future as they move toward adulthood. The staff at the hospital can discuss this with you.

Possible long-term side effects

Radiotherapy can sometimes affect growth and development, and sometimes normal breast development. Not all children will develop long-term side effects. Your child’s doctor or nurse can discuss this with you in detail.

A child having radiotherapy to the chest area may develop the following side effects.

Difficulty with swallowing

About 2−3 weeks (but sometimes only a few days) after radiotherapy to the chest has started, your child may tell you that their chest feels tight, making it difficult for them 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 which your child’s doctor can prescribe. They may also prescribe painkillers, or liquid medicines, for your child to take before meals, to make eating less uncomfortable. This difficulty usually gets better on its own in about 5−8 weeks.

Feeling sick

Some children find that their treatment makes them feel sick, and sometimes they may actually be sick. This is most common when the treatment area is near the stomach. Tell your specialist if your child experiences any nausea or vomiting as they can prescribe anti-sickness drugs (anti-emetics). These drugs are usually very successful. Any feeling of sickness usually stops once treatment is over.

Breathlessness

After radiotherapy to their chest, your child may have a dry cough and experience breathlessness. This may not occur until several months after the treatment. If you notice this, you should tell your child’s doctor, who may give treatment with steroids and possibly antibiotics.

Possible long-term side effects

Radiotherapy can sometimes affect growth and development, and sometimes normal breast development. Rarely, radiotherapy to the left side of the chest can affect your child’s heart. Not all children will develop long-term side effects. Your child’s doctor or nurse can discuss this with you in detail.

Radiotherapy to the head and neck area may cause the following side effects.

Effects on the mouth

Radiotherapy to the mouth may make your child more likely to get tooth decay. They will need to see a specialist dentist before treatment begins, to make sure their teeth and gums are as healthy as possible. Once treatment has finished, your child will need more frequent check-ups at the dentist. Fluoride treatment can often help to protect their teeth against the effects of radiotherapy. Your doctor may refer them for special dental treatment before radiotherapy starts.

Sore mouth Your child’s mouth may become sore, as the cells that line it are sensitive to radiation. The glands that produce saliva may also be affected by the treatment, causing them to produce little, or no, saliva. This can make it uncomfortable for your child to chew or swallow. Radiotherapy may also make your child more prone to getting mouth infections, such as thrush. These can be treated with medicines. The staff in the radiotherapy department can advise you on how to look after your child’s mouth, and about foods that can help them.

Taste changes Your child’s taste buds may also be affected by treatment. They may notice changes in the way food tastes. Some people describe it as having a ‘metallic' taste, while others say that all foods taste the same. As the effects of treatment fade away, things return to normal, but it may take up to a year for your child’s sense of taste to return.

Support with eating and drinking If eating and drinking become too painful, a thin tube may be passed up your child’s nose and down into their stomach (a nasogastric or NG tube). Special liquid foods can be given through the NG tube. Another way of giving liquid foods is through a central line, which is inserted into a vein in your child’s chest, or by passing a tube (a PEG tube) through the wall of your child’s abdomen and into the stomach. This will be done while they are under general anaesthetic. Staff will explain in detail what this involves, and will include you in decisions about the best way to feed your child.

Hair loss

Radiotherapy only causes hair to fall out in the treated area, but this can happen where the radiation beam leaves the body (for example on the back of the neck), as well as where it enters the body. Ask your child’s doctor to show you exactly where their hair will fall out. It usually begins to fall out after 2−3 weeks. Often, the hair starts to grow back within 2−3 months of treatment ending. Sometimes it grows back a slightly different colour and texture, and possibly not quite as thick as before.

Losing hair can be very distressing for children, but there are many ways of dealing with it. There are wigs, hats, and head-coverings for children.

Drowsiness

If your child has radiotherapy to their head, about 4–6 weeks after treatment has ended, they may start to feel extremely sleepy and drowsy. They may also experience headaches, fevers, nausea and vomiting, and unsteadiness. These symptoms are often similar to those your child had at diagnosis, which can seem worrying. However, these symptoms are to be expected, and are known as ‘somnolence syndrome’. They gradually get better over about 2–3 weeks.

Endocrine problems

Radiotherapy given to the head or the neck can sometimes affect the endocrine system. This is a network of glands that make hormones which circulate around the body in the blood. The pituitary gland in the brain (which produces hormones that control other endocrine glands in the body), and the thyroid gland in the neck may be affected by radiotherapy. If the pituitary gland is involved, this can affect normal growth development and can sometimes lead to fertility problems. If radiotherapy affects the thyroid gland, this can reduce the amount of thyroid hormone in the body (hypothyroidism). Symptoms of hypothyroidism include: fatigue, weakness, weight-gain, hair loss, and muscle cramps.

If your child develops hormonal problems, it will usually be possible for them to have hormone replacement therapy to help correct any symptoms. Your child’s doctor or specialist nurse can explain this.

Possible long-term side effects

Radiotherapy can sometimes affect growth and development, and may cause the muscles in the neck to develop unevenly, or the face to become asymmetrical. This sounds very worrying, but support is available from specialist staff who can help you and your family cope with any long-term side effects that occur. It is important to remember that not all children will develop long-term side effects.

Your child will have regular check-ups, in the children’s (paediatric) or adolescent cancer clinic. The doctors will monitor them regularly for signs of any problems or long-term side effects.

As a parent, the fact that your child has cancer is one of the worst situations you can be faced with. Knowing that they need radiotherapy treatment which may cause side effects, can also be very difficult. You may have many different emotions, such as fear, guilt, sadness, anger and uncertainty. These are all normal reactions, and part of the process that many parents go through at such a difficult time.

Our section on living with cancer talks about the emotional impact of caring for a child with cancer, and suggests sources of help and support.