Leukemia incidence in the Russian cohort of Chernobyl emergency workers

Abstract

Of all potentially radiogenic cancers, leukemia, a type of cancer of the blood, has the highest risk attributable to ionizing radiation. Despite this, the quantitative estimation of radiation risk of a leukemia demands studying very large exposed cohorts, because of the very low level of this disease in unexposed populations and because of the tendency for its radiation risk to decrease with time. At present, the Japanese cohort of atomic bomb survivors is still the primary source of data that allows analysis of radiation-induced leukemia and the underlying dose-response relationship. The second large cohort that would allow to study radiation-induced leukemia is comprised of individuals who were exposed due to the accident of the Chernobyl nuclear power plant in 1986. The objective of the present study was to estimate radiation risks of leukemia incidence among the Russian cohort of Chernobyl emergency workers, for different time periods after the accident. Twenty-five years after the Chernobyl accident and based on the results of the present study, one can conclude that the radiation risk of leukemia incidence derived from the Russian cohort of Chernobyl emergency workers is similar to that derived from the cohort of atomic bomb survivors: The time-averaged excess relative risk per Gray (ERR Gy(-1)) equals 4.98 for the Russian cohort and 3.9 for the life span study (LSS) cohort; excess absolute risk decreases with time after exposure at an annual rate of 9% for the Russian cohort, and of 6.5% for the LSS cohort. Thus, the excess in risk of leukemia incidence in a population due to a single exposure is restricted in time after exposure by the period of about 15 years.

Hematological Malignancies in Chernobyl Clean-Up Workers (1996-2010)

“…In fact, a number of authors have predicted and reported the increased incidence of leukemia among clean-up workers in Russia, Belarus and Ukraine. According to Ivanov et al, the dynamics of standardized incidence ratio demonstrates a 2.5-3-fold increase in the leukemia incidence in Russian cohort of Chernobyl clean-up workers in 5-7 years after the accident [7] . Prisyazhniuk et al stated statistically significant increment in observed-to-predicted ratio of leukemia and lymphoma incidence: 2.6 in 1990-1993 and 2.0 in 1994-1997 [8] .…”

Initial Diagnostic Workup of Acute Leukemia: Guideline From the College of American Pathologists and the American Society of Hematology

“…76 As noted in the preceding section, a history of radiation therapy-either alone or in combination with chemotherapy for prior neoplastic or nonneoplastic conditions-is recognized as being associated with an increased risk for AL, particularly AML. Radiation exposure for individuals near natural disasters or atomic bomb explosions is also associated with an increased risk of leukemia, 77,78 and reportedly, radiation exposure after diagnostic procedures, including computed tomography scans in children, increases the risk for leukemia. 79,80 Patients receiving hematopoietic stem cell therapy are at increased risk for development of MDS and AML.…”

“…[81][82][83] The incidence appears to be increased in older patients and in patients who received total-body radiation. 78 Exposure to certain chemicals is associated with an increased risk of development of AL, particularly AML. Benzene exposure, especially at high levels, is associated with an increased risk of AML.…”

Letter to the Editor: On the Radiation-Leukemia Dose-Response Relationship among Recovery Workers after the Chernobyl Accident

“…Considering the above, the studies (Ivanov et al 2012;Zablotska et al 2013) provide no conclusive evidence of an incidence increase of leukemia due to ionizing radiation after the Chernobyl accident. At the same time, such reports give rise to the statements in some reviews about "a two-fold increase in the incidence of leukemia between 1986 and 1996 in Russian emergency and recovery operation workers exposed to external dose of more than 150 mGy" (Balonov 2013), which is not in agreement with the above-cited conclusions by the UNSCEAR (2000,2008).…”

“…Furthermore, Ivanov et al (2003Ivanov et al ( , 2012 used the "age-specific Russian male population rates" for an external comparison (Ivanov et al 2003). The counterpart of the liquidators in the population -middle-aged men -have generally not been covered by medical examinations; their access to modern health care has been limited (Jargin 2013).…”