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Radiation Therapy for Thymus Cancer

Radiation therapy is the use of high-energy radiation in the form of x-rays or radioactive particles to kill cancer cells.

When is radiation therapy used for thymus tumors?

Radiation therapy can be used in many ways to treat thymus tumors (thymomas and thymic carcinomas):

  • It is often used after surgery if the doctor thinks that some cancer was left behind.
  • Even when no visible tumor was left after surgery, radiation therapy is sometimes given to try to kill any small areas of cancer that may have been left behind because they were too small to see. This is called adjuvant therapy. It's done for nearly all stage II, III, and IV thymomas and for most thymic carcinomas.
  • Some people who can’t have surgery might be treated with radiation therapy alone. Sometimes chemotherapy is given with radiation to help it work better.
  • For people with advanced disease, radiation therapy can sometimes help ease (palliate) symptoms from the cancer such as shortness of breath, pain, bleeding, or trouble swallowing.

How is radiation therapy given?

The type of radiation therapy used most often to treat thymic cancer is external beam radiation therapy (EBRT). This type of radiation therapy uses x-rays from a machine outside the person’s body to kill cancer cells. Advanced forms of EBRT that allow the radiation beams to be aimed more precisely, such as 3D conformal RT (3D-CRT), intensity-modulated RT (IMRT) are often used to treat these tumors. Newer forms of radiation therapy might also be options in some centers. (See What's New in Thymus Cancer Research?)

Before your treatments start, the medical team will take careful measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. They will also do special CT scans to help plan your treatments.

The treatment is much like getting an x-ray, but the radiation is more intense. The procedure doesn't hurt, but it does cause side effects (discussed below). Each treatment lasts only a few minutes, although the setup time — getting you into place for treatment — usually takes longer. Most often, radiation treatments are given 5 days a week for several weeks.

Possible side effects of radiation therapy for thymus tumors

Common side effects of radiation therapy include:

  • Fatigue
  • Skin changes where the radiation passes through, such as redness and blistering
  • Nausea and vomiting
  • Irritation of the esophagus (the tube between the mouth and stomach), which could cause painful swallowing and eating problems
  • Poor appetite and weight loss
  • Diarrhea (if the abdomen/belly or pelvis is treated)

Radiation can damage bone marrow leading to low blood counts. This can lead to anemia (low red blood cell counts) which can cause people to feel weak and tired. It can also lead to low white blood cell counts, which increases the risk of serious infections.

Chest radiation therapy can also damage the lungs. This can lead to trouble breathing and shortness of breath. It usually gets better after radiation treatments stop, but sometimes the damage is long-term (or even permanent).

Most side effects are short-term and get better over time after radiation treatment is done.

If radiation therapy is given along with chemotherapy, the side effects are often worse.

If you are having any side effects from radiation therapy, tell your doctor or nurse. Most often, there are ways to help control these symptoms.

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 editors and translators with extensive experience in medical writing.


Meneshian A, Oliver KR, Molina JR. Clinical presentation and management of thymoma and thymic carcinoma. UpToDate. 2024. Accessed at on May 14, 2024.

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines): Thymomas and Thymic Carcinomas. Version 1.2024. Accessed at on May 14, 2024.


Last Revised: May 15, 2024

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