Following the accident at the Chernobyl nuclear power plant, hundreds of thousands of clean-up workers were exposed primarily to external radiation with those sent earliest receiving the highest doses. (140 mGy in 1986, 90 mGy in 1987 and 40 mGy in 1988-89). Studies of cancer among clean-up workers have focused on leukemia. Investigators in DCEG have conducted a case-control study of leukemia and other hematological diseases based on a large cohort of male clean-up workers from Ukraine (~110,000). Individual doses to the bone marrow were estimated using a new method developed for this study. In part because of the intriguing findings, the study has been extended to accrue cases for an additional five years.
In a separate study of cancer incidence among Chernobyl clean-up workers from Estonia and Latvia, DCEG investigators did not observe a significantly elevated risk of leukemia. Thyroid cancer was increased, but this appeared to be due largely to screening.
For more information on both studies, contact Kiyohiko Mabuchi.