How it Works

High doses of radiation are designed to kill cells or keep them from growing and dividing (cancer is defined as the abnormal, uncontrolled growth of the body’s cells). Radiation therapy can be an effective approach for treating cancer because cancer cells grow and divide more rapidly than many of the body's normal cells. Interestingly, although some normal cells are affected by radiation, normal cells may recover faster from the side effects of radiation therapy than do cancer cells.

Radiation Therapy Benefits

Many people with cancer are treated with radiation therapy. Radiation can be used before surgery to help shrink a tumor. After surgery, radiation therapy may be effective in stopping the growth of any cancer cells that remain in the body. Even when attempts to cure cancer are not possible, radiation therapy may still bring relief – a treatment approach known as palliative care. Many patients find the quality of their lives improved when radiation therapy is used to shrink tumors, thereby reducing pressure, bleeding, pain or other cancer symptoms.

External and Internal Radiation

Radiation therapy is delivered in one of two ways, either externally or internally. Most people receive external therapy, in which a machine directs the high-energy rays at the tumor and at a small margin of normal tissue surrounding it. When internal radiation is used, the radiation source is placed inside the body in a treatment known as brachytherapy or implant therapy. Implants may be thin wires, catheters, capsules or “seeds.” An implant may be placed directly into a tumor or inserted into a body cavity. Sometimes, after a tumor has been surgically removed, the implant is placed in the area from which the tumor was taken out to kill any tumor cells that may remain.