Scientific Protocol for the Study of Leukemia and Other Hematologic Diseases Among Clean-up Workers in Ukraine Following the Chernobyl Accident

Leukemia holds a special place in the study of radiation-related cancer because bone marrow is one of the tissues most sensitive to the carcinogenic effect of ionizing radiation, radiogenic leukemia has the shortest latent period among radiation-induced cancers, and its appearance suggests that solid tumors may follow. These same characteristics also contribute to its considerable significance in radiation protection. There are, nevertheless, important gaps in existing knowledge of radiation-induced leukemia, gaps that derive from characteristics of the study of the atomic bombing of Hiroshima and Nagasaki, and from studies of the effects of medical irradiation and studies of nuclear workers, these being the studies that have provided most of the information to date. These gaps include the presumed reduction in risk resulting from dose-fractionation and low dose-rate, and the time-response function in the first five years after exposure. The primary objective of this study is to investigate leukemia risk as a function of such radiation; it would constitute the largest epidemiologic study conducted to date among working-age males, a group of particular concern in establishing occupational radiation safety standards. In addition, data on cases of multiple myeloma and myelodysplasia identified in the cohort will be collected to test the hypothesis of a dose related association between radiation and increased risk for each of these diseases. The primary scientific objectives of the proposed study are to test the following hypotheses: (a) that there is a dose-related increase in risk of leukemia among these liquidators; (b) that the magnitude of any observed risk per unit dose is less than that seen in the atomic bomb survivors, exposed to essentially instantaneous radiation. Subsidiary objectives include: (a) to investigate the nature of the dose-response relationship among liquidators and to identify modifiers of risk, including time since exposure, age at exposure, etc.; (b) to test the hypothesis that there is a dose-related increased risk of multiple myeloma; (c) to test the hypothesis that there is a dose-related increased risk of myelodysplasial; (d) to collect and store buccal cells from about 2,000 liquidators with a wide range of dose estimates extending to well over 1 Gy for possible use in future molecular studies of their DNA.

Sex

All

Minimum age

18 Years

Maximum age

70 Years

* INCLUSION CRITERIA:

We intend to include in the proposed study all 350 clean-up workers with "historical" records and 150 proxies to be identified by the liquidators; however, we anticipate a considerable number of them will not be available for the study due to deaths, not being able to be traced, no response, refusals, etc. The study subjects will be interviewed in person. All study subjects are males, median age of early liquidators is 64 y while for clean-up workers sent to mission is about 61 years.

EXCLUSION CRITERIA:

Excluded from the study will be those who have been found to be deceased, cannot be located, refuse to participate in the study, or do not provide informed consent.

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• BACKGROUNDChumak VV, Romanenko AY, Voilleque PG, Bakhanova EV, Gudzenko N, Hatch M, Zablotska LB, Golovanov IA, Luckyanov NK, Sholom SV, Kryuchkov VP, Bouville A. The Ukrainian-American study of leukemia and related disorders among Chornobyl cleanup workers from Ukraine: II. Estimation of bone marrow doses. Radiat Res. 2008 Dec;170(6):698-710. doi: 10.1667/RR1403.1. PMID 19138037
• BACKGROUNDZablotska LB, Bazyka D, Lubin JH, Gudzenko N, Little MP, Hatch M, Finch S, Dyagil I, Reiss RF, Chumak VV, Bouville A, Drozdovitch V, Kryuchkov VP, Golovanov I, Bakhanova E, Babkina N, Lubarets T, Bebeshko V, Romanenko A, Mabuchi K. Radiation and the risk of chronic lymphocytic and other leukemias among chornobyl cleanup workers. Environ Health Perspect. 2013 Jan;121(1):59-65. doi: 10.1289/ehp.1204996. Epub 2012 Nov 8. PMID 23149165