Thymus Cancer: Radiation Therapy

What is radiation therapy?

Radiation therapy uses high-energy beams of X-rays or particles to kill cancer cells or stop them from growing.

When might radiation therapy be used?

Radiation is part of the treatment for some thymus tumors. Your healthcare provider may suggest this treatment for any of these reasons:

• 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 case, radiation is often given along with chemotherapy. This is sometimes called chemoradiation.

• To ease symptoms  caused by tumors that can't be treated with surgery or that have spread to other organs. For instance, to shrink a tumor that's causing swallowing or breathing problems.

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

What happens during radiation therapy

A healthcare provider who specializes in cancer and radiation is called a radiation oncologist. This provider works with you to decide the kind of radiation you need. They also figure out the dose and the length of time you need treatment.

The most common way to get radiation for a thymus tumor is by external radiation. The radiation comes from a large machine that focuses an invisible beam of energy at the tumor. In most cases, special types of external radiation are used to try to limit the doses of radiation reaching nearby normal cells. This includes intensity-modulated radiation therapy (IMRT) and 3-D conformal radiation therapy (3D-CRT).

Most people get external radiation on an outpatient basis in a hospital or clinic. This means you go home after each treatment. Treatment is often given 5 days a week for many weeks.

Getting ready for radiation

Before your first radiation treatment, you’ll have an appointment to figure out exactly where on your body the radiation beam needs to be directed. This is called simulation. It may take up to 2 hours. During this session, imaging tests, such as CT or MRI scans, may be done. These tests help your healthcare providers know exactly where the tumor is so they can aim the radiation right at it. Also at this session, you may have body molds made to help put you in the exact same position and keep you from moving during each 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 semipermanent ink or tattoos. 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 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, but it takes longer, up to 15 to 30 minutes. You should plan on being there for about an hour total.

At the start of the treatment session, a radiation therapist helps you get into position. They may use blocks or special shields to protect parts of your body from exposure to the radiation. The therapist then lines up the lights on the machine with the marks on your skin so the radiation is directed to the right spot. When you’re ready, the therapist leaves the room and turns the machine on. You may hear whirring or clicking noises as the machine moves around you. This may sound like a vacuum cleaner. The machine won't touch you. During the session, you’ll be able to talk to and hear the therapist over an intercom. The therapist can see you the whole time. You can’t feel radiation, so the process won't hurt. You will not 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 do have them, your healthcare provider may change the dose of radiation or how often you get treatments. Or your healthcare provider may stop treatment until the side effects clear up. Tell your healthcare provider about any side effects you have right away. It's important to treat them before they get worse.

If chemotherapy is given along with radiation, the side effects tend to be worse.

Possible short-term side effects

Common short-term side effects include:

• Extreme tiredness (fatigue)

• Skin irritation or changes where the radiation goes into your body. This can include redness, like a bad sunburn. Your skin may blister and peel.

• Nausea or vomiting

• Mouth or throat sores

• Burning feeling, tightness, or pain when swallowing and eating

• Poor appetite

• Weight loss

Most side effects tend to go away over time after you stop treatment. Still, if you have any side effects, talk with your healthcare provider about how to deal with them. You should also ask what side effects you might expect and what to do if they become serious. Make sure you know what number to call with questions or problems. Is there a different number for evenings and weekends?

Most side effects can be treated, and some can even be prevented.

Potential long-term side effects

Radiation can cause some long-term side effects that may not show up until many years after treatment. These depend on the dose of radiation and where it was aimed. This is a special concern when 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.