Approximately half of all cancer patients will receive radiation therapy at some time during their management. Radiation therapy can sometimes be used instead of surgery, and is often the preferred treatment for a number of cancers including cancer of the larynx, other oral cancers, prostate, breast, brain and lung. In many situations, radiation therapy is given following surgery, which may not have completely removed all tumor tissue. Radiation therapy is also very effective at controlling local symptoms caused by cancer, such as bone pain from the spread of cancer into the bone.

In radiation therapy, a precisely measured dose of radiation is directed to a tumor. Radiation is able to destroy cancer cells by damaging their DNA, causing these cells to die at cell division. During the delivery of radiation therapy, the radiation beam enters the body on one side and exits out the body on the other side without deviating in direction. Unfortunately, some normal tissue is also exposed to radiation in the area the beam was aimed, and can be harmed. Fortunately, with the technology available today, most normal tissue is spared, resulting in much less damage to healthy tissue and far fewer side effects than in years past.