Assessment of radiation risks of malignant neoplasms among the population of Russian regions contaminated with radionuclides as a result of the Chernobyl accident

Some areas of the Russian Federation were contaminated with radionuclides released as a re-sult of the Chernobyl accident. The current paper clarifies some items of the previously published study based on NRER (National Radiation-Epidemiological Registry, the Registry) data. The pre-vious issue presented estimates of radiation risks of cancer incidence among the population of four the most contaminated regions of the Russian Federation: Bryansk, Kaluga, Oryol and Tula oblasts. Risks of thyroid cancer are estimated with account of screening effect. The cohort con-sisted of more than 327 thousand people resided in the contaminated areas. The average dose to the thyroid of children and adolescents was 0.174 Gy, the average dose to the thyroid of adults was 0.035 Gy. Thyroid cancer was diagnosed in 1549 members of the cohort during the follow-up period from 1991 over 2019, among them 423 cases were children and adolescents at the accident and 1126 cases were adults. Significant increase in thyroid cancer incidence was ob-served in adults exposed internally through the intake of iodine-131 at a young age. The statisti-cally significant radiation risk of thyroid cancer persists over 30 years after exposure. The risk de-creases with increasing the attained age. In people exposed to radiation before the age of 1 year and reaching the age of 20 years, the coefficient of excess relative risk of thyroid cancer (ERR/Gy) was 4.61. Radiation associated thyroid cancer is attributed to 20.6% of the cohort mem-bers exposed internally through the intake of radioiodine isotopes in their childhood and adoles-cence, and thyroid cancer from intake of radioiodine is attributed to 58% of cases exposed to ra-diation under 4 years of age. Marked screening effect (ES) was found during the disease diag-nosing, screening coefficient was 5.6 for children and 2.1 for adults. There were not attributed to radiation statistically significant risks of solid cancers, including radiation induced breast cancer in females, in the cohort of people resided in the areas contaminated with radionuclides. Radia-tion risk of leukemia was also not identified, although the average value of excess relative risk in men exceeded zero. Further observations of the cohort of persons resided in areas contaminated with radionuclides will increase the statistical power of radiation-epidemiological studies and clarify the assessment of radiation risks of human for chronic exposure at low doses.

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Comparison of early forecasts of the incidence of thyroid cancer in residents of the Russian Federation after the Chernobyl accident with observational data

Radiatsionnaya Gygiena = Radiation Hygiene ◽

10.21514/1998-426x-2021-14-4-45-59 ◽

2021 ◽

Vol 14 (4) ◽

pp. 45-59

Author(s):

I. A. Zvonova ◽

M. I. Balonov

Keyword(s):

Thyroid Cancer ◽

Thyroid Gland ◽

Children And Adolescents ◽

Russian Federation ◽

Chernobyl Accident ◽

Radioactive Fallout ◽

Radiation Induced ◽

The Russian Federation ◽

Regions Of Russia

A review of methods for assessing doses in the thyroid gland, predictions of the long-term consequences of its irradiation and the actual incidence of thyroid cancer in residents of four regions of the Russian Federation with the most significant radioactive fallout after the Chernobyl accident are presented. The method for assessing doses in the thyroid gland is based on the results of monitoring in May-June 1986 of radioiodine in the environment, food and in the body of residents. Thyroid doses in the population were used to justify medical and social protection measures, as well as epidemiological studies. In addition, the authorities needed forecasts of the possible morbidity of the population in order to organize adequate medical care. Most of the thyroid cancer cases were predicted among the adult population, which was not confirmed by observations 35 years after the accident. The prognosis of the incidence of thyroid cancer in preschool children differed in different studies due to the use of different coefficients of reducing the biological effectiveness of 131I radiation in the thyroid gland and long-term external and internal irradiation of the whole body with a low dose rate compared to the effect of acute exposure. The increase in the incidence of thyroid cancer among children began five years after the accident at the Chernobyl nuclear power plant. Examples of the dynamics of the incidence for children in the Bryansk region of the Russian Federation are given. The 2018 UNSCEAR Report showed that for 1986-2015, among children and adolescents under 18 years of age on the day of the accident in Belarus, Ukraine and four regions of Russia, more than 19 thousand thyroid cancer cases were detected, of which the share of radiation-induced diseases was estimated at 25%. For four regions of Russia, this amounts to 460 cases with a range of possible estimates from 130 to 900 cases. The highest morbidity was manifested among younger children exposed at the age of 0-4 years. In older children and adolescents, the proportion of radiation-induced diseases has significantly decreased 30 years after the accident. In general, early forecasts of radiation-induced thyroid cancer incidence in children in four regions of the Russian Federation with high levels of radioactive fallout are consistent with the data of subsequent 30-year epidemiological observations within an order of magnitude. With regard to thyroid cancer in adults, such a comparison is difficult, since no radiogenic increase in the incidence has been detected.

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Radiation-epidemiological studies of thyroid cancer incidence in Russia after the Chernobyl accident (estimation of radiation risks, 1991-2008 follow-up period)

Radiation Protection Dosimetry ◽

10.1093/rpd/ncs019 ◽

2012 ◽

Vol 151 (3) ◽

pp. 489-499 ◽

Cited By ~ 37

Author(s):

V. K. Ivanov ◽

V. V. Kashcheev ◽

S. Y. Chekin ◽

M. A. Maksioutov ◽

K. A. Tumanov ◽

...

Keyword(s):

Thyroid Cancer ◽

Cancer Incidence ◽

Chernobyl Accident ◽

Epidemiological Studies ◽

Radiation Risks ◽

Accident Estimation ◽

Thyroid Cancer Incidence

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Medical Radiological Consequences after 35 Years after the Accident at the Chernobyl NPP

Medical Radiology and radiation safety ◽

10.12737/1024-6177-2021-66-6-5-9 ◽

2021 ◽

Vol 66 (6) ◽

pp. 5-9

Author(s):

L. Il'in ◽

V. Ivanov ◽

I. Linge ◽

V. Kashcheev ◽

O. Kochetkov ◽

...

Keyword(s):

Thyroid Cancer ◽

Power Plant ◽

Nuclear Power Plant ◽

Russian Federation ◽

Chernobyl Accident ◽

Nuclear Power ◽

Chernobyl Nuclear Power Plant ◽

Malignant Neoplasms ◽

Radiation Doses ◽

The Russian Federation

Purpose: In an article prepared on the basis of the conclusion of the Russian Scientific Commission on Radiological Protection (RSCRP) at the Department of Medical Sciences of the Russian Academy of Sciences "Assessment of the radiological consequences of the Chernobyl accident after 35 years according to the National Radiation and Epidemiological Register" (NRER), the main conclusions of the large-scale radiation-epidemiological studies carried out. Material and methods: The work uses information NRER – liquidators of the consequences of the Chernobyl accident and the Branch Register of FMBA of Russia – liquidators. When assessing the excess relative risk of malignant neoplasms, the EPICURE. Results: The current status of the National Radiation and Epidemiological Register, which is currently functioning within the framework of the Law of the Russian Federation of 30.12.2012 No. 329-FZ “On Amendments to Certain Legislative Acts of the Russian Federation in terms of ensuring that changes in the health status of certain categories of citizens are taken into account exposed to radiation". For the first time in an integral form, the article presents the medical radiological consequences of the accident at the Chernobyl nuclear power plant for the population of Russia. It was found that an increase in the incidence of thyroid cancer due to incorporated exposure to 131I was found in a cohort of children and adolescents (28 856 people) who received radiation doses of more than 200 mGy in 1986. There was no increase in the incidence of thyroid cancer among the adult population. Analysis of the incidence of solid cancers in the territories of the Bryansk, Kaluga, Tula and Oryol regions contaminated with radionuclides did not reveal an increase in the frequency of this pathology for children and adults. It is shown that in the cohort of liquidators of the Chernobyl accident, who received radiation doses of more than 150 mGy (35 303 people), an increase in the incidence of leukemia during the first 11 years after the accident at the Chernobyl nuclear power plant and solid cancers was revealed in comparison with the spontaneous level. Conclusions: The article points out serious limitations associated with a high degree of uncertainty in the received personal dosimetric data on liquidators in 1986–1987. and the need to use the total dose from all types of radiation (professional, emergency, medical, natural) to calculate the radiation risk. RSCRP emphasizes the high urgency of continuing work on reducing the uncertainty of dosimetry data and assessing the radiological consequences of the Chernobyl accident based on a comprehensive analysis of the NRER data.

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