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Radiation treatment is the use of high energy rays (such as x-rays) to kill cancer cells or shrink tumors. External beam radiation is given in a way much like the x-rays used to find broken bones, but the radiation is stronger.

The total dose of radiation is broken into small amounts given over a couple of weeks. Your child may be fitted with a plastic mold that looks something like a body cast. This is to keep him or her in the same position each time so that the radiation can be aimed at the right spot. Your child will lie on a special table while a machine gives the radiation. The treatment does not hurt. Each session lasts about 15 to 30 minutes, with most of the time being spent making sure the radiation is aimed correctly. Some younger children may be given medicine to make them drowsy before each treatment.

Radiation is often part of the treatment for more advanced Wilms tumors (stages III, IV, and V) and for some earlier stage tumors with unfavorable histology. (See the section "What is Wilms tumor?" for more on histology.)

Possible side effects of radiation therapy

Radiation is often an important part of treatment, but young children’s bodies are very sensitive to it. Doctors try to use as little radiation as they can to help avoid or limit any problems.

Radiation therapy can cause both short-term and long-term side effects. Side effects depend on the dose of radiation and where it is aimed.

Possible short-term effects:

  • Mild sunburn-like changes and hair loss
  • Severe skin reactions.
  • Nausea or diarrhea.
  • Fatigue

Possible long-term effects:

  • Radiation therapy can slow the growth of normal body tissues (such as bones). This is less likely with the lower doses of radiation used today.
  • Radiation that reaches the chest area can affect the heart and lungs.
  • Radiation to the abdomen in girls may damage the ovaries. This might lead to problems with periods or with getting pregnant or having children later on.
  • Radiation can damage DNA. As a result, it slightly increases the risk of getting a second cancer later, usually many years after the radiation is given. This doesn't happen often with Wilms tumor because the amount of radiation used is low.

Parents should have their child watched closely by doctors so that they can treat any problems quickly if they do come up. See the section, "Moving on after treatment" for more on the possible long-term effects of treatment.

To learn more about radiation treatment, see our document, Understanding Radiation Therapy: A Guide for Patients and Families.

Last Medical Review: 08/01/2012
Last Revised: 08/01/2012