- Cancer is the uncontrolled growth of abnormal cells anywhere in a body.
- There are over 200 types of cancer
- Anything that may cause a normal body cell to develop abnormally potentially can cause cancer; general categories of cancer-related or causative agents are as follows: chemical or toxic compound exposures, ionizing radiation, some pathogens, and human genetics.
- Cancer symptoms and signs depend on the specific type and grade of cancer; general signs and symptoms are not very specific but are as follows: fatigue, weight loss, pain, skin changes, change in bowel or bladder function, unusual bleeding, persistent cough or voice change, fever, lumps, or tissue masses.
Quick GuideUnderstanding Cancer: Metastasis, Stages of Cancer, Pictures
What is 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.
What are the types of radiation therapy?
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 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.
What are the side effects of radiation therapy?
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.
Medically reviewed by Jay B. Zatzkin, MD; American Board of Internal Medicine with subspecialty in Medical Oncology
Radiation therapy techniques in cancer treatment
Medically Reviewed by a Doctor on 6/26/2015