Radiation therapy (also known as radiotherapy) uses radiation to destroy cancer cells. Radiation damages normal cells as well, but cancer cells are especially sensitive to its effects. This makes radiation therapy a good treatment option for many cancer types.
Radiation therapy can be used:
- before surgery, to shrink the tumour and make it easier to remove
- after surgery, to destroy any remaining cancer cells
- as the main treatment
- in combination with surgery, chemotherapy or stem cell transplant
- to relieve symptoms caused by the tumour.
Radiation therapy for children is given in a radiation oncology department in an adult hospital located near a children’s hospital. Doctors who specialise in radiation therapy for children will give the treatment to your child. These doctors are called paediatric radiation oncologists and follow international practice.
Radiation therapy typically involves a course of treatment given over many days or weeks. Each treatment is called a fraction. Normally your child will receive 1 fraction each day until the total dose is reached and the course of treatment is completed.
Infants and young children can have radiation therapy although chemotherapy if often used instead, allowing radiation therapy to be given once a child is older.
All radiation therapy aims to concentrate the radiation dose to the tumour very carefully and limit the amount of radiation to other areas of the body.
Types of radiation therapy
The type of radiation therapy your child will have depends on the type and location of the cancer.
External radiation therapy
External radiation therapy (called external beam radiation) uses a machine that delivers a beam of radiation to the tumour. The area that receives the radiation is very exact. This lessens the amount of radiation to surrounding healthy areas.
External radiation therapy does not make your child radioactive.
Your child might have external radiation therapy 5 times per week (with a 2-day weekend rest) and continuing for several weeks. Each fraction (treatment) will take a few minutes. The treatment itself is painless.
In the week or so before radiation treatment begins, you will need to bring your child to the radiation department to plan the treatment (simulation). The session involves placing your child on a treatment bed in a way that is comfortable and can be reproduced for each treatment. Your child will need to lie very still for about 15 minutes. Typically, there is a ‘bean bag’ on the treatment bed that is moulded to the child’s shape. A mask of the head and neck area is made when the tumour is in this area. The mask is worn only for treatment and stays in the radiation department. Both the bean bag and face mask are painless to make and involve no injections or needles.
The treatment team will make every effort to ensure that your child is comfortable during treatment planning and delivery. Play therapists are often part of the team in the radiation department. Very young children may need to have a general anaesthetic to ensure they lie still. Radiation treatment is not painful.
Internal radiation therapy
Radiation therapy can also be given internally and over a very short distance. This is called brachytherapy. It involves giving radiation through a needle, hollow tube (catheter) or another specialised device that has been made in advance. Any needles or catheters are placed in position in the operating theatre at the children’s hospital on the day of radiation treatment, or the day before. A paediatric surgeon works with the paediatric radiation oncologist. Sometimes the devices stay in place for a few days. Depending on the treatment and the dose of radiation, your child may need to stay in the children’s hospital and make a visit to the radiation department once or twice a day for treatment over several days.
Most brachytherapy is delivered in a special room in the radiation department. There is no radiation once the session is finished even though a device may remain inside your child’s body. This is called ‘high dose rate’ brachytherapy.
Occasionally ‘low dose rate’ brachytherapy is used. This means that radioactivity is slowly delivered inside the body over several days. If this is the case, your child’s doctor will discuss this with you in more detail.
Side effects of radiation therapy
The most common side effects of radiation therapy during the course of treatment are:
- a skin reaction localised to the radiation site, typically dryness, itchiness or redness. Occasionally there is peeling and rarely blistering (similar to sunburn) when high doses of radiation are needed. Many children have no skin reaction.
- Nausea or diarrhoea when the tumour is in the stomach, abdomen or pelvic area
These side effects usually settle within 1 or 2 weeks of the treatment finishing.
Radiation treatment can have longer term side effects. These are very dependent on the part of the body treated and the dose of radiation treatment. Your radiation oncologist will explain these in detail. Radiation treatment is only recommended when the benefit (chance for cure or symptom relief) outweigh the consequences of treatment.
Radiation therapy affects each person differently.
Medicines and other treatments can help deal with many side effects and make your child feel more comfortable. Your child’s doctor will discuss these with you.