About Radiation Therapy

Understanding Radiation Therapy

For many people, the word “radiation” conjures up frightening images. But radiation therapy, also called radiotherapy, is an effective, carefully controlled means of fighting cancer. Although therapy can cause side effects, the treatment sessions themselves are painless. And in the skilled hands of a radiation oncologist and well-trained technologist, the side effects can be minimized. Radiation therapy is one of the most common treatments for cancer; it is used in more than half of all cases.

What exactly is it?

Radiation therapy uses beams of high-energy waves or particles (for example, x-rays, gamma rays, or alpha and beta particles) to kill or damage cancer cells. The powerful stream of energy, which is thousands of times more intense than the rays used for a routine chest x-ray, damages the DNA of cancer cells, rendering them unable to reproduce and grow. Although radiation damages both cancer cells and normal cells, normal cells are able to repair themselves and function properly.

When is it used?

Radiation therapy is the primary treatment for many types of cancer, including certain cancers of the lung, breast, cervix, prostate, testicles, bladder, thyroid, larynx and brain, as well as early-stage Hodgkin’s disease and non-Hodgkin’s lymphoma.

In some cases, radiation therapy is the only treatment needed; in others, it is used in combination with surgery or chemotherapy. Radiation can be used before surgery to shrink a tumor so that it is easier to remove. After surgery, it is used to destroy microscopic extensions of cancerous tissue around a tumor that surgery might have missed.

Unlike chemotherapy, in which cancer-killing drugs travel throughout the entire body via the bloodstream, radiation therapy affects only the tumor and the surrounding tissue.When cancer has spread to distant areas of the body, chemotherapy is needed.

How is it given?

Radiation can be administered in several ways. Most people receive external radiation therapy (or external beam radiation) during outpatient visits to a hospital or clinic. This requires the patient to lie on a table while a machine directs the radiation at the cancer. Before treatment begins, the doctor defines the target area in a process called simulation. This involves a series of x-rays to pinpoint the treatment field (also called the treatment port), which is then outlined with semi-permanent ink so that it can be used for future treatment sessions. Simulation ensures that the radiation beam is aimed correctly.

The dose of radiation and the number of treatments depend on the type, size, and location of the cancer, as well as the patient’s overall health. In general, radiation is given five days a week for five to eight weeks. Taking the weekends off gives normal cells a chance to recover.

Internal radiation is another way to administer therapy. It involves implanting a tiny radioactive source in the form of a wire or pellet sealed in a small container. The implant, which can be permanent or temporary, is placed directly into (or near) the tumor. Internal radiation can also be given using unsealed radioactive sources that are taken orally or by injection.

With internal radiation therapy, the body may emit a small amount of radiation. If a patient receives a sealed implant, it is unlikely that the radioactive substance could escape, but precautions (for instance, staying in hospital and limiting visitors) are taken anyway. Because fetuses are vulnerable to the smallest doses of radiation, pregnant women are not allowed to visit. Unsealed internal radiation usually requires a hospital stay. Patients are kept isolated until their bodies no longer contain enough radioactivity to be harmful to others.

Side effects
Like all cancer therapies, radiation therapy can have side effects. These include: skin irritation, temporary change in skin color in the treated area, temporary or permanent loss of hair in the area being treated, and fatigue. Other side effects depend on the area of the body being treated.

Self-care during therapy
Patients undergoing radiation therapy need to get lots of rest, eat a balanced diet to prevent weight loss, and be as gentle as possible to the skin in the treatment area. Self-care advice specific to certain treatments and their side effects will be given by the doctor or nurse. Be sure to raise any questions you have.