Radiation of certain wavelengths, called ionizing radiation, has enough energy to damage DNA and cause cancer. Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation. Epidemiological studies provide the data needed to quantify cancer risks based on dose and to establish radiation protection standards. Leukemia and most solid cancers have been linked to radiation.
Most solid cancer data are reasonably well described by linear dose response functions, although there may be a decrease in risks with very high doses. People exposed early in life have especially high relative risks for many types of cancer, and the risk of solid, radiation-related cancer seems to persist throughout life. Some cancer treatments, such as chemotherapy and radiation therapy, can increase a person's risk of developing a different type of cancer later in life. Here we look at the risk of second cancers that may be related to previous cancer treatment.
Nakamura explained that radiation-induced cancers can occur in pediatric cancer survivors, who are often given intensive chemoradiation therapy. They can also occur in adult cancer survivors. Radiation-induced cancers can arise at a wide range of intervals after cancer treatment, from several years to decades. While these cancers most commonly occur in a wide variety of solid tissues, blood cancers can also arise after radiation therapy, he said.
Exposure to ionizing radiation is the best-established and oldest environmental cause of human breast cancer, in both men and women. Most scientists agree that no safe dose of radiation has been identified. Ionizing radiation is any form of radiation with enough energy to separate electrons from atoms (i.e., ionize atoms).