Mortality from cancers of major sites in female radium dial workers

The female radium dial workers have now experienced significant mortality from cancers other than the bone sarcomas and head carcinomas long known to be radium induced. The relationships of radium exposure to mortality from cancers of the stomach, pancreas, colon, rectum, liver, lung, breast, cervix, and corpus uteri, and from leukemia were studied in 1,285 pre-1930 dial workers. Mortality was compared with that expected from rates for US white females, with and without adjustment for local area mortality rates, and with mortality in dial workers exposed from 1930 to 1949. For the 693 cases whose body content of radium has been measured since 1955, dose-response relationships of cancer to systemic intake of radium and duration of employment were examined. Liver, pancreatic, cervical, and uterine cancers were clearly unrelated to radium exposure. Other cancers of the digestive tract appeared to be indirectly, if at all, associated with work in radium facilities. Lung cancer requires further investigation; inhalation exposures of the dial workers were reviewed. Analyses of the breast cancer data uncovered several observations inconsistent with the previously suggested causal association with radium exposure. Multiple myeloma was also reviewed. A threefold excess risk of death due to multiple myeloma has occurred, but is more closely correlated with duration of employment (a surrogate for external gamma radiation) than with radium intake.