Radiation therapy uses a stream of high-energy particles or waves, such as x-rays, gamma rays, electrons and protons, to destroy or damage cancer cells.

Some patients receive radiation treatments alone or in combination with surgery, chemotherapy or biologic therapy.

Doctors can use radiation before surgery to shrink a tumor so that it can be removed more easily or after surgery to stop the growth of any cancer cells that remain.

How does radiation therapy work?

Radiation therapy uses special equipment to deliver high doses of radiation to cancerous tumors, killing or damaging them so they cannot grow, multiply or spread.

Unlike chemotherapy, which exposes the entire body to cancer-fighting chemicals, radiation therapy affects only the tumor and the surrounding area.

How is radiation therapy given?

Most patients receive external radiation. A machine, called a linear accelerator, directs high-energy rays at the cancer and some normal surrounding tissue.

Most people receive external radiation therapy during outpatient visits to a hospital or treatment center. You will probably be scheduled for treatments five days per week for four to six weeks.