Radiation Therapy for Kaposi Sarcoma

Radiation therapy uses high-energy radiation to kill cancer cells. When the radiation is given from outside the body it is called external beam radiation therapy. This is the type of radiation therapy used to treat lesions of Kaposi sarcoma (KS). KS lesions usually respond well to radiation treatments, but sometimes new lesions can appear in the skin right next to the area where the radiation was given.

Radiation therapy is often effective as a type of local therapy to treat KS lesions on or near the surface of the body. Radiation is used to reduce symptoms like pain or swelling from the KS lesions. It is also used for skin lesions that look bad and can easily be seen (like on the face).

For KS lesions on the skin, the form of radiation most often used is called electron-beam radiation therapy (EBRT). It uses tiny particles called electrons that don’t pass very far through the skin’s surface. This limits non-skin side effects. EBRT can also be used to treat large areas of the skin if a person has many widespread KS lesions.

Radiation can also be used to treat KS lesions in the mouth or throat. The form of radiation used for this, known as photon radiation, can penetrate deeper into the body.

Radiation treatments for KS lesions are often given once a week for several weeks. Getting treatment is much like getting an x-ray, but the radiation is stronger. The procedure itself is painless. Each treatment lasts only a few minutes, although the initial setup time takes longer.

Side effects of radiation therapy can include skin changes, nausea, vomiting, and fatigue, Radiation can also cause anemia (low red blood cells), as well as lower numbers of white blood cells, which increases the risk of infection.

Serious side effects are rare when radiation is given to just a small area of the skin, but a small portion of patients have severe skin reactions.

When radiation is used to treat KS lesions in the mouth or throat, these areas can become painful and open sores can develop. If chemotherapy and radiation are given at the same time, the side effects can be worse.