Radiation therapy (also known as radiotherapy) uses radiation to destroy cancer cells. Although radiation damages normal cells as well, cancer cells are especially sensitive to its effects, making radiation therapy an effective 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, if surgery is not a good option
- in combination with surgery, chemotherapy or stem cell transplant
- to relieve symptoms of the tumour.
All radiation therapy for children is given in adult radiotherapy units by people who specialise in radiation therapy for children (paediatric radiation oncologists), in line with international practice.
Radiation therapy involves a total dose of radiation, which is split into fractions. Normally one fraction will be given each day over several days until the total dose is reached.
Radiation therapy is not normally given to infants and young children because it can have significant long-term effects. Young children usually have chemotherapy instead. They may have radiation therapy once they are old enough. If radiation therapy is included in your child’s treatment, special care will be taken to reduce the risks.
Depending on where the tumour is and whether it has spread, high doses of radiation can be aimed precisely at the tumour, which limits the amount of radiation that reaches other areas of the body.
Types of radiation therapy
There are two main types of radiation therapy – external and internal – and these each have several subtypes. Examples of subtypes are proton therapy, electron beam radiation, gamma knife and cyber knife. Not all these types of therapy are available in Australia, but it may be possible to access them overseas.
The type of radiation therapy recommended for your child depends on the type and location of the cancer.
External radiation therapy
External radiation therapy (called external beam radiation) uses a machine that aims a beam of radiation onto the tumour. The area that receives the radiation is very precise, to minimise the amount of radiation reaching surrounding healthy areas.
External radiation therapy is usually given 5 times per week (with a 2-day rest), and can continue for several weeks. Each exposure will take a few minutes.
The treatment itself is painless, but it can be uncomfortable for your child because they need to keep very still so that the radiation beam can be directed very precisely at the tumour. Children are usually kept still in some way. They might be held with tape or sponges, or have a mould fitted to their body that puts them in the correct position for the radiation therapy. This can be constrictive and uncomfortable, especially if the material is placed around the head or neck.
The treatment team will make every effort to ensure that your child is comfortable and not in any pain during the procedure. This may include diversion therapy, or a general anaesthetic to make the child sleep.
External radiation therapy does not make your child radioactive.
Internal radiation therapy
Radiation therapy can also be given internally. This is called brachytherapy. It involves giving radioactivity via a needle, a catheter or another specialised device. These stay in place from a few minutes to a few days. Depending on the treatment and the dose of radiation, your child may need to stay in the hospital or make a visit each day for treatment.
After internal radiation therapy, your child will give off radiation for a short time. If this will only be for a few minutes, your child will be put in a separate room so that others are not exposed to the radiation.
If the radioactivity will last for longer and your child is allowed to leave the hospital, you will need to take some safety precautions. Certain people (e.g. pregnant women, children, adolescents) should not get too close to your child until the radiation weakens. Your child’s doctor will discuss this with you in more detail.
The two most common side effects of radiation therapy are:
- skin problems, especially at the radiation site, such as dryness, itchiness, peeling and blistering (similar to sunburn)
Your child may have other side effects, depending on where the radiation therapy is given:
- head or neck – dental problems, mouth problems (dryness, difficulty swallowing) or jaw stiffness
- chest – stiffness in the area and some lung inflammation
- stomach and belly – nausea, vomiting and/or diarrhoea
- pelvis – diarrhoea and urination problems, and reproductive problems later in life.
Radiation therapy affects each person differently – your child may experience none, some or many of these side effects.
Medicines and other treatments are available to help deal with many of these side effects and make your child feel more comfortable. Your child’s doctor will discuss these with you.
Some of these side effects seem quite severe, and can be very distressing for you and your child. However, the benefits of radiation therapy usually outweigh the risks. Your child’s doctor will discuss the risks and benefits with you.