What is radiation therapy?
Radiation therapy (also called radiotherapy, x-ray therapy, or irradiation) is the use of a certain type of energy (called ionizing radiation) to kill cancer cells and shrink tumors. Radiation therapy injures or destroys cells in the area being treated (the “target tissue”) by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue. There are different types of radiation and different ways to deliver the radiation. For example, certain types of radiation can penetrate more deeply into the body than can others. In addition, some types of radiation can be very finely controlled to treat only a small area (an inch of tissue, for example) without damaging nearby tissues and organs.
About 50 to 60 percent of cancer patients are treated with radiation at some time during their disease. Radiation therapy is the careful use of high-energy radiation to treat cancer. A radiation oncologist may use radiation to cure cancer or to relieve a cancer patient’s pain. Radiation therapy works because the radiation destroys the cancer cells’ ability to reproduce and the body naturally gets rid of these cells. A cancer patient may be treated with radiation alone. Prostate cancer and larynx cancer are often treated in this manner. Sometimes radiation therapy is only part of a patient’s treatment. For example, a woman may have radiation therapy after breast conserving surgery. She can be cured of her cancer and still keep her breast. When radiation therapy is only part of a patient’s treatment it is called adjuvant treatment. Patients can be treated with radiation therapy and chemotherapy before surgery.
