Thymus Cancer: Radiation Therapy

By Mayer, Deborah K RN, MSN, AOCN®, FAAN 
March 21, 2017

Thymus Cancer: Radiation Therapy

What is radiation therapy?

Radiation therapy uses high-energy radiation from X-rays or particles to kill cancer cells.

When might radiation therapy be used?

Radiation can be part of the treatment for some thymus tumors. There are several reasons your health care provider may recommend this therapy:

  • To try to kill any cancer cells that might be left after surgery. When radiation is used after surgery, it’s called an adjuvant therapy. 

  • To try to shrink a tumor before surgery. This might make it easier to remove. When radiation is used before surgery, it’s called a neoadjuvant therapy.

  • To treat the tumor if you can't have surgery for some reason. In this situation, radiation is often used with chemotherapy.

  • To ease symptoms caused by tumors that can't be treated with surgery or that have spread to other organs.

To plan your treatment strategy, meet with a team of cancer specialists. This might include a surgeon, radiation oncologist, and medical oncologist.

What happens during radiation therapy

The most common way to receive radiation for a thymus tumor is from a machine outside your body. This machine releases an invisible X-ray beam. This is called external radiation. Sometimes special types of external radiation are used to try to limit the doses of radiation reaching nearby normal cells. This includes such as intensity-modulated radiation therapy (IMRT).

A doctor who specializes in cancer and radiation is called a radiation oncologist. This doctor works with you to determine the kind of radiation you need. This doctor also figured out the dose and how long you need treatment.

You can normally receive external radiation on an outpatient basis in a hospital or a clinic. This means that you can go home after treatment. Most people receive external radiation five days per week for several weeks.

Preparing for radiation

Before your first radiation treatment, you’ll have a session to figure out exactly where on your body the radiation beam needs to be directed. The process is called simulation. This session may take up to two hours. During this session, you may have imaging tests, such as computed tomography (CT) scans or magnetic resonance imaging (MRI) scans. These can help your healthcare providers know the exact place of your tumor to better aim the radiation. Also at this session, you may have body molds made to help keep you from moving during the treatment. Then, you’ll lie still on a table while a radiation therapist uses a machine to define your treatment field. The field is the exact area on your body where the radiation will be aimed. Sometimes it’s called your port. The therapist may mark your skin with tiny dots of semi-permanent ink. This is done so the radiation will be aimed at the exact same place each time. 

On the days you get radiation

On the days you get radiation treatment, you’ll lie on a table while the machine is placed over you. You may have to wear a hospital gown. It’s a lot like getting an X-ray, only longer. It takes about 15 to 30 minutes to complete. You should, though, plan on being there for about an hour.

At the start of the treatment session, a radiation therapist may place blocks or special shields to protect parts of your body that don’t need to be exposed to radiation. The therapist then lines up the machine so that radiation is directed to the spot that was marked during the simulation. When you’re ready, the therapist leaves the room and turns the machine on. You may hear whirring or clicking noises, similar to the sounds of a vacuum cleaner, while the radiation is being given. During the session, you’ll be able to talk to the therapist over an intercom. You can’t feel radiation, so the process will be painless. Also, you won’t be radioactive afterward.

What to expect after radiation therapy

Because radiation affects normal cells as well as cancer cells, you may have some side effects. The side effects from radiation are usually limited to the area being treated. Some people have few or no side effects. But if you have them, your healthcare provider may change the dose of radiation or how often you receive treatments. Or your healthcare provider may stop treatment until the side effects are cleared up. Be sure to tell your healthcare provider about any side effects you have.

Potential short-term side effects

These are some of the common short-term side effects:

  • Skin irritation or changes in areas on your body that receive radiation

  • Nausea 

  • Fatigue

  • Irritation of your esophagus. This could lead to pain when swallowing.

  • Loss of appetite and weight loss

If you have any of the side effects, ask your healthcare provider or nurse about how to deal with them. Also ask how to know when they become serious. These side effects normally go away a few weeks after you stop getting treatment.

Potential long-term side effects

Radiation can cause some long-term side effects. These depend on where the radiation was aimed. This is a special concern in treating tumors in young adults. Long-term side effects can include:

  • Lung damage. Radiation might harm your lungs. This could lead to trouble breathing and shortness of breath.

  • Increased risk of heart disease. This includes heart attacks.

  • Second cancers. Cancers are more likely to form in areas that have received radiation. These cancers may form even decades after treatment.


March 21, 2017


Clinical Presentation and Management of Thymoma and Thymic Carcinoma. UpToDate.

Reviewed By:  

Alteri, Rick, MD,Gersten, Todd, MD