Radiation therapy for Wilms tumour

Radiation therapy uses high-energy rays or particles to destroy cancer cells. It is sometimes used to treat Wilms tumour. The healthcare team will consider your child’s personal needs to plan the type and amount of radiation, and when and how it is given. Your child may also receive other treatments.

Radiation therapy is given for different reasons. It is sometimes used to treat children with Wilms tumour that is more advanced or has anaplastic (unfavourable) histology. Radiation therapy may be given just to the kidney area or to the entire abdomen depending on the spread of the tumour. Radiation therapy may be given to the chest to treat Wilms tumour that has spread to the lung.

Your child may have radiation therapy to:

• destroy cancer cells left behind after surgery and chemotherapy to reduce the risk that the cancer will come back (recur) (called adjuvant therapy)
• relieve pain or control the symptoms of recurrent Wilms tumour that is not responding to chemotherapy (called palliative therapy)

The following types of radiation therapy are most commonly used to treat Wilms tumour.

During external radiation therapy, a machine directs radiation through the skin to the tumour and some of the tissue around it. The radiation therapy team will base the size of the treatment area on the amount of cancer present. Very young children may be sedated before radiation therapy to keep them still during treatment.

Radiation therapy is given to the abdomen as soon as possible after surgery to remove the tumour. Doctors base when to give radiation on the histology of the tumour. Radiation therapy is usually given within 14 days of surgery to remove Wilms tumour.

Modern radiation techniques allow doctors to target the area to be treated much more accurately, while sparing as much surrounding normal tissue as possible.

In 3D-CRT, the radiation oncologist uses MRI images to map the exact location and shape of the tumour. Several radiation beams are then shaped and aimed at the tumour from different directions to treat the tumour from all angles. Each individual beam is fairly weak and less likely to damage normal tissues. A higher dose of radiation is delivered where the beams meet at the tumour.

IMRT is similar to 3D-CRT in that it delivers radiation from many different angles to treat the entire tumour. In addition to shaping and aiming the radiation beams, IMRT allows the radiation oncologist to adjust the strength of the individual beams. This allows a higher dose to be delivered to the tumour and reduces the dose of radiation reaching nearby normal tissues.

Side effects can happen with any type of treatment for Wilms tumour, but every child’s experience is different. Some children have many side effects. Other children have few or none at all.

During radiation therapy, the healthcare team protects healthy cells in the treatment area as much as possible. But damage to healthy cells can happen and may cause side effects. Side effects can happen any time during, immediately after or a few days or weeks after radiation therapy. Sometimes late side effects develop months or years after radiation therapy. Most side effects go away on their own or can be treated, but some side effects may last a long time or become permanent.

Side effects of radiation therapy will depend mainly on the size of the area being treated, the specific area or organs being treated, the total dose of radiation, the treatment schedule and the child’s age.

Some common side effects of radiation therapy to the abdomen used for Wilms tumour are:

• low blood cell counts
• fatigue
• skin problems
• nausea and vomiting
• loss of appetite
• diarrhea
• radiation enteritis (inflammation of the intestines with cramping or diarrhea)
• kidney problems
• ulcers

Some common side effects of radiation therapy to the chest used for Wilms tumour are:

• fatigue
• skin problems
• difficulty swallowing

Other side effects can develop months or years after treatment for Wilms tumour. Find out more about late effects of treatments for Wilms tumour.

Tell your child’s healthcare team if your child has these side effects or others you think might be from radiation therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help your child deal with them.

Find out more about radiation therapy and side effects of radiation therapy. To make the decisions that are right for your child, ask the healthcare team questions about radiation therapy.