Radiation therapy is a powerful tool in the war against cancer, along with chemotherapy and surgery. It works by inflicting irreversible damage to the cancer cells' DNA, which destroys their ability to reproduce. Normal healthy cells are able to repair DNA damage that might be caused by the radiation exposure, but cancer cells cannot.
A cancer patient may be treated with radiation alone or in conjunction with chemotherapy and/or surgery. When radiation therapy is only part of a patient's treatment, it is called "adjuvant treatment." By treating a patient with radiation therapy and/or chemotherapy, the oncology team may make it possible for a patient to avoid surgery or have less radical surgery than would otherwise be required. After the surgical removal of a cancerous mass, radiation can be used (with or without chemotherapy) to kill very small deposits of cancer that cannot be seen and removed during surgery.
