Kaposi Sarcoma: Radiation Therapy

March 21, 2017

Kaposi Sarcoma: 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 therapy can be used to treat Kaposi sarcoma (KS) lesions on the skin or in the mouth. This is a type of local therapy, meaning it only treats cancer in a specific part of the body, instead of treating the whole body. Radiation therapy is typically used to treat lesions on the face or lesions that are causing symptoms (like pain or swelling) but that are too large to be treated with other types of local therapy.

To plan your entire treatment strategy, you might consult with a team of cancer specialists. This will include a doctor who specializes in radiation therapy, called a radiation oncologist, and other types of doctors.

What happens during radiation therapy?

The most common way to get radiation therapy for KS is from a machine outside your body that emits a beam of radiation. This is called external radiation. Two main types of external radiation can be used to treat KS lesions:

  • Electron-beam radiation therapy (EBRT). This is typically used for lesions on the skin. This type of radiation doesn't penetrate deeper than the skin, which limits the side effects it causes.

  • A beam of X-rays (photons). This is used for lesions in the mouth or throat. This type of radiation can penetrate deeper into the body.

Your radiation oncologist will work with you to figure out the kind of radiation you need. This doctor also determines the dose and how long you need the therapy.

You can usually get external radiation therapy on an outpatient basis in a hospital or a clinic. Outpatient means you go home the same day. The typical treatment for KS is to get radiation once a week for several weeks.

Before your first treatment, you might have a session to determine exactly where on your body the radiation beam needs to be directed. The process is called simulation.

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. The experience is much like getting an X-ray, only longer. It takes about 15 to 30 minutes to complete. But you should 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 right spot. When you are 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 will be able to talk to the therapist over an intercom. You can’t feel radiation, so the process will be painless. Also, you will not be radioactive afterward.

What to expect after radiation therapy

Radiation affects normal cells as well as cancer cells. Because of this, you may have some side effects from this treatment. But these are usually limited to the area being treated. Some people have few or no side effects. But if you do have them, your doctor may change the dose of your radiation or the frequency of treatments. Or the doctor may stop treatment until the side effects are gone. Be sure you tell your doctor about any side effects you have.

Side effects might include:

  • Skin irritation or changes in areas that get radiation

  • Nausea

  • Fatigue

  • Low blood counts, as noted on a blood test

Sometimes, treated KS lesions (especially in the mouth or throat) can become open sores, which might be painful.

If you have any side effects, talk with your doctor or nurse about how to deal with them and how to know when they become serious. Usually these side effects go away a few weeks after you stop getting treatment.


March 21, 2017


AIDS-related Kaposi sarcoma: Staging and treatment. UpToDate.

Reviewed By:  

Alteri, Rick, MD,Levin, Mark, MD