Estimating of radiation risks of malignant neoplasms among Russian Chernobyl cleanup workers

The paper considers radiation risks of solid cancer incidence and mortality, as well as risk of leu-kemia incidence (other than chronic lymphocytic leukemia) among Russian Chernobyl cleanup workers (liquidators). The study of the cohort of liquidators carried out at the National Radiation Epidemiological Registry (NRER) was based on the follow-up data collected from 1992 over 2019. The size of the Chernobyl cleanup workers cohort exceeded 65 thousand people, their av-erage age at the time of entering the exclusion zone was 34 years, the average external gamma radiation dose received by liquidators during their cleanup work was about 0.133 Gy. Radiation-induced risks of solid cancer incidence and mortality in the study cohort were statistically signifi-cant, the risk magnitude rose with increasing the follow-up length. For the maximum follow-up period, from 1992 over 2019, the excess relative risk coefficient for solid cancer incidence was ERR/Gy=0.62, 95% CI (0.29; 0.98), and excess relative risk coefficient for solid cancer mortality was ERR/Gy=0.74, 95% CI (0.32; 1.22), the estimated coefficients were in good agreement with similar coefficients calcu-lated for the Russian liquidators with the use of ICRP radiation risk models. Non-parametric esti-mates of relative radiation risk within the same dose intervals for solid cancers and for leukemias in the cohort of liquidators were statistically significant for radiation doses above 0.150 Gy. For radiation doses below 0,150 Гр the linear non-threshold model is conservative, i.e. there was ev-idence for statistically significant radiation risk of leukemia incidence among liquidators during the first 11 years after the accident, from 1986 over 1997, ERR/Gy=4.41, 95% CI (0.24; 14.23). In later years, until 2018 there was no evidence of radiation-related risk of leukemia incidence. Out-comes of future studies will impact on optimization of radiological protection, development of reference levels for Russian general public exposure and improvement of the system for delivery of targeted medical care to people exposed to radiation.

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LEUKEMIA INCIDENCE AND MORTALITY OF RECOVERY OPERATION WORKERS OF THE CHERNOBYL ACCIDENT: ASSESSMENT OF RADIATION RISKS FOR THE FOLLOW-UP PERIOD OF 1986–2014

Radiatsionnaya Gygiena = Radiation Hygiene ◽

10.21514/1998-426x-2018-11-4-7-17 ◽

2018 ◽

Vol 11 (4) ◽

pp. 7-17 ◽

Cited By ~ 1

Author(s):

V. K. Ivanov ◽

V. V. Kashcheev ◽

S. V. Karpenko ◽

S. E. Glebova ◽

K. A. Tumanov ◽

...

Keyword(s):

Relative Risk ◽

Chronic Lymphocytic Leukemia ◽

Chernobyl Accident ◽

Radiation Risk ◽

Lymphocytic Leukemia ◽

Excess Relative Risk ◽

Entire Body ◽

Average Dose ◽

Incidence And Mortality

Leukemia incidence in the cohort of Russian male recovery operation workers (liquidators) was estimated at 78110 people for the follow-up period 1986-2014. The average age of the liquidators at the time of entry into the zone of works for liquidation of the Chernobyl accident was 34 years. Radiation risk of leukemia incidence (with the exception of chronic lymphocytic leukemia) was analyzed for liquidators who had official data on the individual dose of external gamma radiation of the entire body accumulated over the period of work. During the follow-up period, 157 cases of leukemia were detected (with the exception of chronic lymphocytic leukemia). Collection and verification of data of hemoblastoses cases among persons exposed to radiation exposure was carried out according to a specially developed algorithm. The average dose of the liquidators was 108 mGy. During the period 1986–1997 was established a statistically significant (p<0.05) linear dose dependence of the leukemia incidence with an excess relative risk of ERR/Gy=4.17 (90% CI: 0.18, 13.24). From 1998 until the end of the follow-up period, as well as for the entire follow-up period (from 1986 to 2014), no statistically significant estimates of excess relative risk were found. For mortality, no statistically significant estimates of excess relative risk and relative risk were found for any of the observation periods. The obtained estimates of the radiation risk of morbidity indicate that a statistically significant excess leukemia incidence of liquidators, which may be associated with external gamma irradiation, is manifested in the first decade after exposure.

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Solid cancer incidence risk in in the Ural cohort of the accidentally exposed population: 1956–2017

Radiatsionnaya Gygiena = Radiation Hygiene ◽

10.21514/1998-426x-2020-13-3-6-17 ◽

2020 ◽

Vol 13 (3) ◽

pp. 6-17

Author(s):

L. Yu. Krestinina ◽

S. S. Silkin ◽

L. D. Mikryukova ◽

S. B. Epifanova ◽

A. V. Akleyev

Keyword(s):

Relative Risk ◽

Cancer Incidence ◽

Chronic Exposure ◽

Excess Relative Risk ◽

Solid Cancer ◽

The Southern Urals ◽

Exposed Population ◽

Incidence Risk ◽

Incidence Analysis

To date, the study of the effects of chronic exposure of the South Ural population has been carried out in two separate cohorts – in the Techa River Cohort and in the East Urals Radioactive Trace Cohort. In 2019, the Ural cohort of accidentally exposed population was formed. It included the population exposed in two radiation situations in the Southern Urals in the 1950s. The number of the combined cohort for the cancer incidence analysis was about 60 thousand people, the follow-up period was extended to 2017, the number of solid cancers was 4537, and the number of person-years was 1283267, which is 3 times more than when analyzing the effects of exposure in each of the two radiation situations separately. In the incidence analysis of all solid cancer types, we used the dose accumulated in the walls of the stomach, which corresponds to the dose accumulated in most organs and tissues with the exception of bone tissue and red bone marrow. The mean dose to the stomach accumulated over the entire follow-up period for cohort members was 38 mGy, the maximum -1.13 Gy. The paper presents the first results of solid cancer incidence risk analysis in the combined cohort, which show a statistically significant dose dependence of the incidence in case of chronic exposure in the range of low and medium doses. The sex and age-averaged excess relative risk value of 0.075/100 mGy (the 95% confidence interval is 0.039–0.113) is comparable to that obtained in the studies of the Japanese cohort of atomic bomb survivors. The statistically significant excess relative risk value of 0.047/100 mGy, obtained separately for men, is in good agreement with that in professional cohorts where men prevail – in the cohort of the Chernobyl NPP accident clean-up workers and in the cohort of professional workers in the three countries (UK, France, USA). The established cohort with a long follow-up period has a great potential for furthermore detailed studies of the effects of radiation and non-radiation factors on public health.

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The influence of follow-up on DS02 low-dose ranges with a significant excess relative risk of all solid cancer in the Japanese A-bomb survivors

Radiation and Environmental Biophysics ◽

10.1007/s00411-016-0667-0 ◽

2016 ◽

Vol 55 (4) ◽

pp. 509-515 ◽

Cited By ~ 2

Author(s):

Linda Walsh ◽

Uwe Schneider

Keyword(s):

Relative Risk ◽

Low Dose ◽

Excess Relative Risk ◽

Solid Cancer ◽

Significant Excess

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Chernobyl cleanup workers from Estonia: follow-up for cancer incidence and mortality

Journal of Radiological Protection ◽

10.1088/0952-4746/33/2/395 ◽

2013 ◽

Vol 33 (2) ◽

pp. 395-411 ◽

Cited By ~ 14

Author(s):

Kaja Rahu ◽

Anssi Auvinen ◽

Timo Hakulinen ◽

Mare Tekkel ◽

Peter D Inskip ◽

...

Keyword(s):

Cancer Incidence ◽

Incidence And Mortality ◽

Cleanup Workers

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Radiogenic risk of solid cancer incidence in persons exposed to radiation in childhood in the Southern Urals

Radiatsionnaya Gygiena = Radiation Hygiene ◽

10.21514/1998-426x-2021-14-1-49-59 ◽

2021 ◽

Vol 14 (1) ◽

pp. 49-59

Author(s):

L. Yu. Krestinina ◽

S. A. Shalaginov ◽

S. S. Silkin ◽

S. B. Epifanova ◽

A. V. Akleyev

Keyword(s):

Relative Risk ◽

Risk Analysis ◽

Cancer Incidence ◽

Southern Urals ◽

In Utero ◽

Excess Relative Risk ◽

Solid Cancer ◽

The Southern Urals ◽

Techa River ◽

Incidence Analysis

The aim of this work is to assess the radiogenic risk of solid cancers incidence in the members of the Urals Childhood Exposure Cohort. The cohort includes people exposed under 20 years of age as a result of two radiation accidents at the Mayak Production Association in the Southern Urals (discharges of radioactive waste into the Techa River and the formation of the East Ural radioactive trace). The number of the cohort for solid cancer incidence analysis is 31,578 individuals. All the members were postnatally exposed and some of them – in-utero. Some of their parents were exposed before conception. 2,018 solid cancers were registered on the incidence catchment area during the period 1956-2018, the total amount of person years was 818,083. The analysis was carried out by the Poisson regression method with a simple parametric excess relative risk model. 95% confidence intervals were estimated with maximum likelihood approach. Only a postnatal dose was used in the first solid cancer incidence analysis of this cohort members with due account for preconception exposure of parents. TRDS-2016 mean postnatal dose accumulated over the entire follow-up period in the stomach of cohort members was 0.047 Gy. The analysis showed linear dependence of solid cancer incidence excess relative risk on postnatal dose. Excess relative risk was 0.66/Gy, р=0.006 with a five-year latency period. While estimating excess relative risk in different age groups at the beginning of exposure, a significant risk was present only in the age group under 1 year and amounted to 2.16/Gy; р<0.02 at the onset of exposure. The present results are in agreement with the results of the solid cancer incidence risk analysis both in the Techa River Cohort of exposed In-Utero where a statistically significant excess relative risk from a postnatal dose was revealed, and with the results of risk analysis in the Japanese cohort of people exposed in-utero and in early childhood.

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Comparison of Radiation Risk of Cancer Incidence among PA Mayak Workers Hired at Different Calendar Periods

Medical Radiology and radiation safety ◽

10.12737/1024-6177-2021-66-6-50-56 ◽

2021 ◽

Vol 66 (6) ◽

pp. 50-56

Author(s):

I. Kuznetsova

Keyword(s):

Relative Risk ◽

Cancer Incidence ◽

Dose Range ◽

Radiation Risk ◽

Incidence Rates ◽

Point Estimate ◽

Solid Cancer ◽

Range Restriction ◽

Epidemiological Analysis ◽

Risk Of Cancer

Purpose: comparative epidemiological analysis of cancer incidence rates among PA Mayak workers hired at different calendar periods. Material and Methods: The cohort of PA Mayak workers hired at reactors, radiochemical, plutonium, water preparing and repair plants in 1948-1982 was selected for analysis of solid cancer (except lung, liver and bone) incidence. The cohort was divided into two subcohorts 1948-1958 and 1959-1982 years of hire. Regression models of relative risk included the description of background rates and excess radiation risk was used. Results: The radiation relative risk per 1 Gy was (ERR/Gy: 0.11; 95 % CI: 0.02; 0.21) in the subcohort of workers hired in 1948–1958 and was close to the estimates from previous studies for the whole cohort. In the subcohort of workers hired in 1959–1982 the point estimate of ERR/Gy was 3 times higher than in the subcohort 1948–1958 years of hire, but it was not statistically significant in the whole dose range. Restriction of doses up to 2 Gy allowed to get significant estimate of ERR/Gy (0.45; 95 % CI: 0.04; 0.95), which 4 times higher the estimate in the first subcohort calculated with the same restriction (0.11; 95 % CI: -0.01; 0.25). All subcohorts differences were not statistically significant and we can say about point distinctions only.

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Determination of increased radiation risk group among Russian Chernobyl cleanup workers

Radiation and Risk Bulletin of the National Radiation and Epidemiological Registry ◽

10.21870/0131-3878-2021-30-1-147-156 ◽

2021 ◽

Vol 30 (1) ◽

pp. 147-156

Author(s):

S.Yu. Chekin ◽

◽

V.V. Kashcheev ◽

M.A. Maksioutov ◽

A.N. Menyajlo ◽

...

Keyword(s):

Medical Care ◽

Risk Group ◽

Radiation Risk ◽

Critical Value ◽

Solid Cancer ◽

Radiation Doses ◽

Use Of Resources ◽

The People ◽

Cleanup Workers

One of the main tasks of the National Radiation Epidemiological Registry (NRER) is monitoring the health status of people exposed to radiation as a result of the Chernobyl accident, and provid-ing them with targeted medical care. To optimize the use of resources dedicated to mitigating health effects of the accident, it is reasonable to identify the people at the higher radiation risk, needing the priority medical care. Radiation risk is directly proportional to radiation dose the indi-viduals received, and also depends on the age, sex of the exposed persons and their baseline (in the absence of radiation) risk rates. Among all the people been registered in the NRER the Cher-nobyl cleanup workers (liquidators) received the highest radiation doses. To determine the group of higher radiation risk of solid cancer among liquidators, an estimate of the attributable radiation fraction, ARF, was used. Among the all liquidators observed in the NRER in 2020, 709 persons, 1.45%, were at the higher risk group of solid cancer, with ARF values exceeding the critical value of 15%. If the critical value of ARF drops to 10%, the group at the higher risk increases to 28% of the total number of the cohort members. The size of the group at the higher risk can be increased or reduced with the use of critical ARF values, depending on the current social and economic sit-uations. However, according to the international experience and assessment results presented in the paper, the critical ARF value may be selected within the range between 10 and 20%.

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