Previous Radiation Exposure in Patients With Leukemia

Twenty-three of 423 adults (5.4%) with acute or chronic leukemia between 1966 and 1971 had received prior radiation exposure. Nineteen had acute leukemia, and four had chronic leukemia. Three patients had been occupationally exposed to radiation, 14 had received therapeutic radiation for malignant diseases, and six for nonmalignant diseases. The annual incidence of radiation exposure among the patients of this study was 6% during 1966 through 1968, 3% during 1969 and 1970, and 10% during 1971. The frequency of previous radiation exposure in patients with leukemia increased substantially during the last year of the study.