Radiation therapy is one of the most common treatments for cancer. It is primarily used to treat certain types of cancer—for example, non-melanoma skin cancers, head and neck cancers, early-stage Hodgkin’s disease, and non-Hodgkin’s lymphomas.
Radiation therapy—also called radiotherapy or X-ray therapy—involves treating cancer with beams of high-energy particles, or waves, such as gamma rays or X-rays. Radiation treatments damage cells by destroying the genetic material that controls how cells grow and divide. And while both healthy and cancerous cells are damaged by radiation, the goal of treatment is to hurt as few normal, healthy cells as possible.
You may be worried about radiation destroying healthy cells as well as the cancerous cells. But radiation is much more harmful to cancer cells than it is to normal cells. This is because cancer cells divide more rapidly than do healthy cells. Cells are more vulnerable to damage when they’re dividing, making cancer cells more susceptible to radiation than normal cells are. In addition, normal cells can recover from the effects of radiation more easily than cancer cells.
Your doctor may suggest radiation therapy as an option at different times during your cancer treatment and for different reasons including:
In addition, radiation therapy is sometimes used to shrink tumors to decrease the pressure, pain, or other symptoms that they may cause. This type of treatment is sometimes referred to as palliative care.
Radiation therapy can be delivered in two ways, externally or internally.
You typically receive external beam radiation on an outpatient basis on a schedule of five days a week for a period of one to eight weeks. In some cases, a single treatment may be used to help relieve pain or other symptoms associated with more advanced cancers.
During a treatment session, you’ll be asked to lie down. You might be positioned with supports to keep you in place and with shields to block radiation from reaching certain parts of your body. The machine may rotate around your body to reach the target from different directions. Treatment sessions generally last 15 to 30 minutes.
Internal radiation can also be given intravenously through an IV, by mouth, or it can be injected into a body cavity. Your doctor may restrict how frequently and closely you have contact with people while you’re receiving internal radiation treatment. This is because some treatments allow radiation to escape, and it’s important to limit unnecessary radiation exposure to others.