Radiation therapy is a form of local treatment that uses high-energy rays to destroy cancer cells. Radiation therapy may be given before, during, or after surgery. Radiation therapy may also be used to relieve pain in certain areas when the tumor cannot be removed.
Radiation therapy may be either internal or external. External radiation is delivered from a machine that aims the rays at the tumor site. External beam radiation is usually given five days a week on an outpatient basis. Internal radiation (often called brachytherapy) comes from radioactive materials (needles, seeds, wires, or catheters) placed in the body directly in or near the tumor. The implant may be permanent or temporary.
Side effects of radiation therapy depend on the dose of radiation and the part of the body that is treated. Fatigue is also a common occurrence for patients receiving radiation treatments. Side effects are usually temporary and can be treated or controlled.