The influence of diagnostic radiography on the incidence of breast cancer and leukemia.

Little accurate information is available on the influence of diagnostic radiography on the incidence of cancer in the general population, largely because of a lack of knowledge of the numbers and the age distributions of patients undergoing radiographic examinations. We used such information from a closed population in Maine that was followed for a year, along with data from the literature on the absorbed dose from typical examinations and a mathematical model linking dose to the incidence rate of cancer, to estimate the numbers of cases of radiologically induced cancer of the bone marrow and breast. Our data indicate that about 1 percent of all cases of leukemia and less than 1 percent of all cases of breast cancer result from diagnostic radiography. In addition, such tumors generally occur late in life; the incidence of radiation-induced leukemia was highest at 69 years, and the incidence of radiation-induced breast cancer was highest at 76 years. Thus, diagnostic radiography has only a small influence on the occurrence of leukemia and breast cancer.