Radiation therapy uses high-energy rays or particles to kill cancer cells.
For more on this, see Treatment by Type and Stage of Wilms Tumor.
The type of radiation used for Wilms tumors is called external beam radiation therapy. Radiation from a source outside the body is focused onto the cancer.
Before treatments start, the radiation team will take careful measurements with imaging tests such as CT or MRI scans to determine the correct angles for aiming the radiation beams and the proper dose of radiation. This planning session is called simulation. Your child may be fitted with a plastic mold that looks like a body cast to keep them in the same position during each treatment so that the radiation can be aimed more accurately.
Radiation is usually given 5 days a week for several weeks. Each treatment is much like getting an x-ray, although the dose of radiation is much stronger. For each session, your child lies on a special table while a machine delivers the radiation from precise angles. Each session lasts about 15 to 30 minutes, with most of the time being spent making sure the radiation is aimed correctly. The actual treatment time is much shorter. The treatment is not painful, but some younger children may be given medicine to make them drowsy or asleep before each treatment to help make sure they stay still.
Modern radiation therapy techniques help doctors aim the treatment at the tumor more accurately than in the past. These techniques may help increase success rates and reduce side effects.
Three-dimensional conformal radiation therapy (3D-CRT): 3D-CRT uses the results of imaging tests such as MRI and special computers to precisely map the location of the tumor. Radiation beams are then shaped and aimed at the tumor from different directions. Each beam alone is fairly weak, which makes it less likely to damage normal body tissues, but the beams converge at the tumor to give a higher dose of radiation there.
Intensity modulated radiation therapy (IMRT): IMRT is an advanced form of 3D therapy. Along with shaping the beams and aiming them at the tumor from several angles, the intensity (strength) of the beams can be adjusted to limit the dose reaching the nearby normal tissues. This lets doctors deliver a higher dose to the tumor. Many major hospitals and cancer centers now use IMRT.
Radiation is often an important part of treatment, but young children’s bodies are very sensitive to it, so doctors try to use as little as possible to help avoid or limit any problems. Radiation therapy can cause both short-term and long-term side effects, which depend on the dose of radiation and where it’s aimed.
Possible short-term effects include:
Possible long-term effects include:
See Living as a Wilms Tumor Survivor for more on the possible long-term effects of treatment.
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Chintagumpala M, Muscal JA. Treatment and prognosis of Wilms tumor. UpToDate. Accessed at www.uptodate.com/contents/presentation-diagnosis-and-staging-of-wilms-tumor on September 4, 2018.
Fernandez CV, Geller JI, Ehrlich PF, et al. Chapter 29: Renal Tumors. In: Pizzo PA, Poplack DG, eds. Principles and Practice of Pediatric Oncology. 7th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2016.
National Cancer Institute. Wilms Tumor and Other Childhood Kidney Tumors Treatment (PDQ®). 2018. Accessed at www.cancer.gov/types/kidney/hp/wilms-treatment-pdq on September 4, 2018.
Last Revised: October 17, 2018