Radiation Therapy

In radiation therapy (also called radiotherapy), invisible high-energy rays or beams of subatomic particles are used to damage cancer cells and can stop them from growing and dividing. This ultimately can kill the cancer cells treated with radiation. A specialist in radiation therapy is called a radiation oncologist.

• Like surgery, radiation therapy can be a local treatment; it affects cancer cells only in the treated area.
• If the area treated is broader, we say it is then a regional treatment.
• Rarely, the whole body is given radiation therapy for a systemic or total-body effect.
• Radiation can come from a machine (external radiation).
• It can also come from an implant (a small container of radioactive material) placed (either temporarily or permanently) directly into or near the tumor (internal or interstitial radiation).
• Some patients receive both kinds of radiation therapy.

External radiation therapy is usually given on an outpatient basis in a hospital or clinic with specialized equipment 5 days a week for a number of weeks. Patients are not radioactive during or after the treatment with external beam radiation therapy.

For internal radiation therapy, the patient often stays in the hospital for a few days. The implant may be temporary or permanent. Because the level of radiation is highest during the hospital stay, patients may not be able to have visitors or may have visitors only for a short time. Once an implant is removed, there is no radioactivity in the body. The amount of radiation given off to the outside from a permanent implant goes down to a safe level before the patient leaves the hospital.

With radiation therapy, the side effects depend on the treatment dose and the part of the body that is treated. The most common side effects are:

• tiredness and
• skin reactions (such as a rash or redness, permanent pigmentation, and scarring) in the treated area.

Radiation therapy can cause inflammation of tissues and organs in and around the body site radiated.

• This can cause symptoms that depend on what organs are affected and to what degree. For example, radiation can inflame skin to cause a burn or permanent pigmentation.
• It can also irritate the colon and cause diarrhea.

Radiation therapy can also cause a decrease in the number of white blood cells, which help protect the body against infection. Today radiation therapy using modern types of equipment can be better focused and thereby result in fewer side effects.

Although the side effects of radiation therapy can be unpleasant, they can usually be treated or controlled. It also helps to know that, in most cases, they are not permanent. Again, the possible side effects of radiation therapy depend on the location and the amount of radiation.