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Radiation Therapy for Chronic Myelomonocytic Leukemia

Radiation therapy is treatment with high-energy rays or particles to kill cancer cells. The most common form of radiation therapy is external beam radiation therapy. The x-rays are aimed at the cancer from a machine outside the patient’s body. The treatment is much like getting an x-ray, but the radiation is more intense. The procedure itself is painless. Before your treatments start, the radiation team will take careful measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. Each treatment lasts only a few minutes, but the setup time -- getting you into place for treatment -- usually takes longer.

If someone who has chronic myelomonocytic leukemia (CMML) is having problems from a very enlarged spleen, radiation therapy may be used to shrink it. Shrinking the spleen can improve symptoms like abdominal (belly) pain and trouble eating, but there are some risks. Treating the spleen with radiation can affect the way it works. Since the spleen helps protect against infections, this can increase the risk of severe infections. If you are considering treatment with radiation for an enlarged spleen, you should talk about the risks and benefits with your doctor. You may also need to get certain vaccines before radiation starts.

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.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Merck Manual. Enlarged Spleen (Splenomegaly).  Accessed October 6, 2017 at

Last Revised: October 25, 2017

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