A case-control study of breast cancer and employment practices among female radiologic technologists was conducted. The cohort from which cases and controls were derived included over 105,000 female medical radiation workers certified by the American Registry of Radiologic Technologists during 1926-1980. Breast cancer cases (n = 528) were individually matched to an average of five control subjects (n = 2628) based on year of birth, year of certification, and length of follow-up. Procedures most commonly performed by controls included fluoroscopy (93%), portable radiographs (92%), routine radiographs (92%), multifilm procedures (87%), dental x-rays (46%), radium therapy (31%), orthovoltage (23%), and cobalt-60 (21%). Breast cancer was not significantly increased with occupational experience with any of these procedures. Furthermore, risk was not related to number of years worked with a particular procedure. This study is reassuring in indicating that medical radiation workers are not at substantial risk for developing radiation-induced breast cancer. However, because only surrogate measures of radiation exposure were available, possibility of a small risk cannot be discounted. Ongoing follow-up of this cohort for incident cancers will incorporate detailed exposure assessment schemes, providing additional information on effects of long-term low-dose radiation through occupation.
(C)1995The American College of Occupational and Environmental Medicine