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Radiation Therapy for Childhood Leukemia
Radiation therapy uses high-energy x-rays or particles to kill cancer cells.
When might radiation therapy be used?
Today, radiation is not often needed to treat leukemia. However, it can be used in certain situations.
In any type of leukemia where a stem cell transplant is part of the treatment plan, radiation to the whole body, called total body irradiation (TBI), can be an important part of the treatment. (see High-Dose Chemotherapy and Stem Cell Transplant).
In some cases, it can be used to treat the spread of acute leukemia outside the bone marrow.
In ALL, cancer cells can spread to the brain or the testicles in males. When this occurs, radiation to the brain or testicle may be considered, especially if treatment with chemotherapy has not been successful. Radiation may be more likely to be used in situations where leukemia has come back (relapsed) after treatment in these areas.
In AML, cancer cells can also spread to the brain or collect outside the bone marrow in tumors called myeloid sarcomas or chloromas. When this occurs, radiation may be used to treat it, especially if treatment with chemotherapy has not been successful. Radiation may be more likely to be used in situations where leukemia has come back (relapsed) after treatment in these areas.
How is radiation therapy given?
This type of treatment is given by a doctor called a radiation oncologist. Before treatments start, the radiation team will take careful measurements with imaging tests, such as a CT or MRI, during a planning session called a treatment simulation.
The treatment itself is like getting an x-ray, but the radiation is much stronger. Each treatment lasts only a few minutes. Most of the time for the treatment is spent making sure the radiation is aimed correctly. The treatment is painless, but some younger children may need to be given medicine beforehand to make sure they do not move during the treatment.
Possible side effects of radiation
The side effects of radiation depend on where the radiation is given and the dose of radiation. The side effects during or shortly after treatment can include:
- Fatigue
- Hair loss in the treated area
- Skin that may be red, tender, or dry like a sunburn in the treated area
- Low blood counts
- Mouth sores, trouble swallowing, and/or loss of appetite (from treatment to the head and neck area)
- Nausea, vomiting, cramps, and/or diarrhea (from treatment to the belly)
Radiation can also have long-term side effects. These are described in After Treatment for Childhood Leukemia.
More information about radiation therapy
To learn more about how radiation is used to treat cancer, see Radiation Therapy.
To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Gramatges MM, O’Brien MM, Rabin KR. Chapter 16: Acute Lymphoblastic Leukemia. In: Blaney SM, Adamson PC, Helman LJ, eds. Pizzo and Poplack’s Pediatric Oncology. 8th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2021.
National Cancer Institute. Childhood Acute Lymphoblastic Leukemia Treatment (PDQ). 2025. Accessed at https://www.cancer.gov/types/leukemia/hp/child-all-treatment-pdq on May 7, 2025.
National Cancer Institute. Childhood Acute Myeloid Leukemia Treatment (PDQ). 2025. Accessed at https://www.cancer.gov/types/leukemia/hp/child-aml-treatment-pdq on May 7, 2025.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Pediatric Acute Lymphoblastic Leukemia. v.3.2025 - March 17, 2025. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/ped_all.pdf on May 7, 2025.
Last Revised: July 22, 2025
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
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