Thyroid Cancer In Belarus Research Articles

Iodine in Soils and Potatoes Produced in Private Farms of Bryansk and Gomel Regions Located in the Impact Zone of the Chernobyl Accident

Among residents of the Bryansk and Gomel regions of Russia and Belarus, who were exposed to the so-called “iodine attack” as a result of the 1986 Chernobyl Nuclear Power Plant accident, there was a sharp increase in thyroid disease. Therefore, the natural iodine deficiency in soils was an important additional risk factor that could cause adverse reactions primarily among children, for whom the incidence of thyroid cancer in Belarus increased by 76 times. Potatoes belong to one of the main ration-forming foods for local population. In this regard, in 2007–2017, 97 settlements were surveyed in the affected areas, in which samples of local arable soils and potatoes were taken from 138 private subsidence farms (PFs).The iodine content in the studied soils of the private farms of the Bryansk region ranged from 0.11 to 3.5 mg/kg (air-dry weight). The content of iodine in potatoes grown on these soils varied within a considerably wider interval: from 0.002 to 0.119 mg/kg (wet weight), averaging 0.033 mg/kg, which indicates a generally low iodine transfer to this particular product. The data obtained deserve attention when organizing monitoring and carrying out measures for the prevention of iodine deficiency.

PO-067 Thyroid cancer incidence in belarusian residents exposed to chernobyl fallout

IntroductionThe accident at the Chernobyl nuclear power plant was the largest radiation-ecological catastrophe, which was accompanied by a massive release of the radioactive isotope of iodine. The aim of this work was to investigate the incidence of thyroid cancer in Belarus and assess the risk of developing this disease in various groups of affected cohorts.Material and methodsThe data from the State Register of persons affected by the Chernobyl accident (from 1987 to 2015) and the data of the Belarusian Cancer Registry (from 1978 to 2015) were used in the study. The analysis was conducted using crude rates (CR), age-specific rates (AsR) and age-standardised rates (ASR) and standardised incidence ratio (SIR). Affected population was divided into four groups: liquidators (99 498 persons), evacuees (13 096 persons), residents of contaminated areas (139 811 persons) and their offspring (30 475 persons), which were analysed by sex, age at time of the disaster, year of being in contaminated area, duration of staying in contaminated area, density of radiation contamination and individualised doze in thyroid gland.Results and discussionsIt was shown the intensive increase in the incidence rates of thyroid cancer in the Belorussian population after the Chernobyl accident, which finished after 2001 (CR1986=1.5±0.24, CR2001=10.3±0.63, CR2015=12.5±0,71). Thyroid cancer growth was most significant in most contaminated Gomel, Mogilev and Brest areas. It was shown that the maximum increase in incidence was observed in persons aged 0–4 years at the time of the accident. In the affected population, significantly high risk of thyroid cancer was noted in all groups. The risk was highest in the evacuees in 1995–1999 (SIR=13.0 (9.21–17.70)) and was significantly higher than in the liquidators (SIR=4.4 (3.63–5.25)) and in the cohort of living in contaminated areas (SIR=2,4 (1.88–2.98)). The risk was higher in men than in women, for those who were children at the time of the accident and who were in the most contaminated areas. The dose-response relationship was shown for the evacuees (rSpearman=0.9, p=0.037) and for persons living in contaminated areas (rSpearman=1.0, p<0.001). For the group of liquidators, the dose-effect relationship was not noted (rSpearman=−0.48, p=0.329).ConclusionIn our work we have shown that Chernobyl disaster increased thyroid cancer incidence in both whole population and most affected groups. Especially in people who were children at the time of disaster.

Major Factors Affecting Incidence of Childhood Thyroid Cancer in Belarus after the Chernobyl Accident: Do Nitrates in Drinking Water Play a Role?

One of the major health consequences of the Chernobyl Nuclear Power Plant accident in 1986 was a dramatic increase in incidence of thyroid cancer among those who were aged less than 18 years at the time of the accident. This increase has been directly linked in several analytic epidemiological studies to iodine-131 (131I) thyroid doses received from the accident. However, there remains limited understanding of factors that modify the 131I-related risk. Focusing on post-Chernobyl pediatric thyroid cancer in Belarus, we reviewed evidence of the effects of radiation, thyroid screening, and iodine deficiency on regional differences in incidence rates of thyroid cancer. We also reviewed current evidence on content of nitrate in groundwater and thyroid cancer risk drawing attention to high levels of nitrates in open well water in several contaminated regions of Belarus, i.e. Gomel and Brest, related to the usage of nitrogen fertilizers. In this hypothesis generating study, based on ecological data and biological plausibility, we suggest that nitrate pollution may modify the radiation-related risk of thyroid cancer contributing to regional differences in rates of pediatric thyroid cancer in Belarus. Analytic epidemiological studies designed to evaluate joint effect of nitrate content in groundwater and radiation present a promising avenue of research and may provide useful insights into etiology of thyroid cancer.

INT-Thyr: Integrating radiation biomarkers into the epidemiology of post-Chernobyl thyroid cancer in Belarus

INT-Thyr: Integrating radiation biomarkers into the epidemiology of post-Chernobyl thyroid cancer in Belarus

Clinical experiences with radiation induced thyroid cancer after chernobyl.

The risk of developing thyroid cancer increases considerably after exposure to external or internal radiation, especially in children below the age of 10. After the Chernobyl reactor accident, the yearly incidence of childhood thyroid cancer in Belarus increased to approximately 40 per 1.000.000 in girls and to roughly 20 per 1.000.000 in boys compared to approximately 0.5 cases per 1.000.000 prior to the accident. Typically, young children with thyroid cancer after radiation exposure present in ≈95% of the cases as papillary cancers, in ≈50% as invasive tumors growing outside the thyroid capsule, in ≈65% with lymph node metastases and in ≈15% with distant metastases. A joint Belarusian-German project starting in April 1993 that combined treatment with surgery and radioiodine was organized in 237 selected children from Belarus who were exposed to the Chernobyl fallout and had advanced stages of thyroid cancer. The study group included 141 girls and 96 boys. Their median age at the time of the accident was 1.7 years; whereas the median age at the time of diagnosis was 12.4 years. With the exception of two cases with follicular histology, the majority of the patients had been diagnosed with papillary thyroid cancers. In 63%, the tumor had grown outside the thyroid capsule and invaded the tissue of the neck (pT4). Nearly all of the selected cases (96%) showed-up with lymph node metastases (pN1) and 43% of the patients with distant metastases mainly to the lungs (pM1). In 58% of the children, complete remissions of thyroid cancer could be achieved until December 31st 2010 and in 34% of the children, stable partial remissions; in the remaining 8% of the patients, partial remissions were observed. The risk of radiation-induced thyroid cancer increased considerably in children and adolescents who were affected by the Chernobyl reactor accident. In spite of the fact, that thyroid cancers in young children seem to behave more aggressively than in older patients, the results of combined treatment with thyroidectomy, radioiodine therapy and thyroid hormone replacement are excellent.

The epidemiological situation of thyroid cancer in Belarus.

Starting in 1990, an increasing number of children in regions adjacent to the site of the Chernobyl nuclear accident have been diagnosed as suffering from thyroid cancer. Using available data up to 1994, the geographical distribution, time and cohort trends, age distribution and other characteristics of this epidemic are reviewed. The results show that the geographical distribution is similar to that of iodine-131 after the nuclear accident. When looking at cohorts of children born in the same years, one can see that the incidence has been increasing steadily since 1990; deviations from this pattern might be explained by active case finding. A causal relationship with the Chernobyl accident appears the most likely interpretation of these results. Possible modifying factors should, however, be examined closely.

Childhood thyroid cancer in Belarus, Russia, and Ukraine after Chernobyl and at present

Thyroid cancer in children is usually rare, but in the individuals exposed to radiation risk of disease increases considerably. After the Chernobyl accident in 1986, an over 10-fold maximal elevation in the incidence of thyroid cancer was registered about a decade later, cumulatively resulting in more than a thousand of newly diagnosed cases in children who lived in the territories of Belarus, Russia, and Ukraine affected by radioactive fallouts. Experience from the epidemic substantially promoted knowledge in clinical pediatric oncology, pathology and basic sciences. This article overviews epidemiology, clinical features, results of treatment and follow-up of childhood patients with radiation-induced Chernobyl thyroid cancer in comparison to sporadic cases diagnosed at present. In addition, we discuss general issues of pathology and molecular findings in childhood thyroid carcinomas.

Thyroid cancer in Belarus after Chernobyl

Abstract. During 20 years after the Chernobyl catastrophe (1986–2005 inclusive) thyroid cancer was diagnosed in more than 12,000 patients of Belarus. The peak incidence in children was observed in 1995 and since 2001 only sporadic cases occur in the age group under 15 years old. In adolescents, the maximum was registered in 2001. By contrast, in the age group of 46 years or over, the current tendency is a marked increase in the number of primary thyroid cancers that dictates a correspondent intensification of special kinds of treatment. Despite a great number of patients, disease-associated mortality remains stably low; the increasing incidence indicates that thyroid malignancies have proved an actual medical problem in 5 of the 6 administrative regions of Belarus.

Childhood thyroid cancer in Belarus

The retrospective analysis was performed to compare the clinical course of radiogenic and sporadic childhood thyroid cancer. The entire series included 752 patients aged less than 15 years at diagnosis. Of them, 686 (91.2%) individuals had radiation history including 681 (90.6%) exposed at the time of the Chernobyl disaster and 5 (0.7%) children were previously treated for malignant lymphoma with an external beam therapy. The second group consisted of 66 (8.8%) unexposed patients. All the children underwent surgery and received suppressive thyroxine therapy with the mean dose of 2.0–2.5 μg/kg of body weight. Radioiodine therapy was performed in 464 (61.7%) cases. The comparison of patients with radiogenic and sporadic thyroid cancer did not reveal statistically significant differences in the distribution of tumor size, histological type or TNM stage. During follow-up time relapses were registered in 204 (27.1%) patients. The main sites of recurrence were the lung or lymph nodes whereas other lesions (thyroid remnants, the bone, soft tissues or CNS involvement) were uncommon. The disease-free survival ranged widely, 0–213 months after the date of primary surgery without significant difference between the radiogenic and sporadic cases. The observed 10-year survival was 99.5% for the entire series, including 99.5% and 99.7% in patients with radiogenic and sporadic carcinomas, respectively.

Clinical Characteristics and Future Trends of Thyroid Cancer in Belarus

Clinical Characteristics and Future Trends of Thyroid Cancer in Belarus

Risk of Thyroid Cancer After Exposure to 131 I in Childhood

After the Chernobyl nuclear power plant accident in April 1986, a large increase in the incidence of childhood thyroid cancer was reported in contaminated areas. Most of the radiation exposure to the thyroid was from iodine isotopes, especially 131I. We carried out a population-based case-control study of thyroid cancer in Belarus and the Russian Federation to evaluate the risk of thyroid cancer after exposure to radioactive iodine in childhood and to investigate environmental and host factors that may modify this risk. We studied 276 case patients with thyroid cancer through 1998 and 1300 matched control subjects, all aged younger than 15 years at the time of the accident. Individual doses were estimated for each subject based on their whereabouts and dietary habits at the time of the accident and in following days, weeks, and years; their likely stable iodine status at the time of the accident was also evaluated. Data were analyzed by conditional logistic regression using several different models. All statistical tests were two-sided. A strong dose-response relationship was observed between radiation dose to the thyroid received in childhood and thyroid cancer risk (P<.001). For a dose of 1 Gy, the estimated odds ratio of thyroid cancer varied from 5.5 (95% confidence interval [CI] = 3.1 to 9.5) to 8.4 (95% CI = 4.1 to 17.3), depending on the risk model. A linear dose-response relationship was observed up to 1.5-2 Gy. The risk of radiation-related thyroid cancer was three times higher in iodine-deficient areas (relative risk [RR]= 3.2, 95% CI = 1.9 to 5.5) than elsewhere. Administration of potassium iodide as a dietary supplement reduced this risk of radiation-related thyroid cancer by a factor of 3 (RR = 0.34, 95% CI = 0.1 to 0.9, for consumption of potassium iodide versus no consumption). Exposure to (131)I in childhood is associated with an increased risk of thyroid cancer. Both iodine deficiency and iodine supplementation appear to modify this risk. These results have important public health implications: stable iodine supplementation in iodine-deficient populations may substantially reduce the risk of thyroid cancer related to radioactive iodines in case of exposure to radioactive iodines in childhood that may occur after radiation accidents or during medical diagnostic and therapeutic procedures.

Thyroid cancer in Belarus

great importance for documenting the evolving pattern of thyroid cancer after Chernobyl and for the understanding of radiation carcinogenesis more generally. Unfortunately, there appear to be severe problems with the data and results as presented. The average populations at risk, calculated from the case numbers and rates in Tables 2 and 3 of the paper by Mahoney and colleagues, are given in Table 1. These figures seem far too low, given that this was a national study on a population of ~10 million (totals for 1997‐2001 are given as an example of this). It seems likely that the incidence rates were in fact calculated per million but reported as if they were rates per 10 5 . There are, however, other less straightforward problems also. The values in the table in bold type are strikingly inconsistent with the rest. In Tables 1 and 3 of the paper, the case numbers and incidence rates (two decimal places) are identical for males, ‘lower exposure’, age 15‐34, and age 35‐54 in each of the two periods 1992‐1996 and 1997‐2001, presumably another error. (There is also some confusion as to whether the final two periods are 1992‐1996 and 1997‐2001, as in paragraph 2 of the methods section and Tables 1 and 2, or 1992‐1995 and 1996‐2001, as in the subsection Trends in ageadjusted incidence rates of the Methods section and Table 3; I have opted for the former.) Finally, four of the incidence rates in Table 1 of the paper differ from those for the same sex-ageperiod-exposure group in Table 2 or 3 of the paper, namely those for females, age 0‐14, 1992‐1996, ‘higher exposure’ and ‘lower exposure’, males, age 35‐54, ‘lower exposure’, and females age 35‐54, ‘higher exposure’; those for age 0‐14 differ by factors of � 6, whereas those for age 35‐54 differ by much smaller amounts. In all four instances I have used the rates in Tables 2 and 3 of the paper to derive the respective populations at risk, because only those rates yield the values for the rate ratio given in Table 1 of the paper. The results presented in the paper as published are impossible to interpret or to quote with any confidence. It would be a great service to all those with an interest in radiation carcinogenesis if the true results of this valuable piece of work could be

Thyroid cancer in Belarus

The Chernobyl accident in April and May of 1986 promoted thyroid carcinomas in 1500 patients who were exposed to radiation at the age group under 18. The common type of malignancy was papillary cancer (93.5%). For the period from 1990 to 2000, thyroid carcinomas were diagnosed in 674 children (age group under 15), in 262 adolescents (age group between 15 and 19) and in 564 young adults (age group from 19 to 33). The highest number of thyroid malignancies in children and adolescents was diagnosed in Gomel and Brest oblasts located closer to the Chernobyl Nuclear Power Plant. For 15 years (1986–2000), spontaneous (non-radiogenic) thyroid carcinomas appeared only in 17 children. Thyroid cancer promoted by radiation in children possesses the behavior to form the regional (73%) and distant (16.6%) metastases, mainly in lung. As a result of performed risk analysis for the cohort exposed at the age group under 18, the following values were obtained: 1.93 (1.79–2.06) per 104 PYGy for the absolute risk coefficient, and 37.66 (35.06–40.26) per Gy for the excess relative risk coefficient.

Ultrasound diagnosis of radiation-induced childhood thyroid cancer in Belarus: 10 years of practical experience

Ultrasound diagnosis of radiation-induced childhood thyroid cancer in Belarus: 10 years of practical experience

Ten-year Chernobyl aid programmes of the Otto Hug Strahleninstitut-MHM: treatment and research projects on thyroid cancer in Belarus

The unexpected serious increase in the incidence of thyroid cancer following the reactor accident in Chernobyl led to considerable research efforts from abroad and the support of Belarus in order to mitigate these health problems. In 1991, the Otto Hug Strahleninstitut-MHM (Otto Hug Radiation Institute), a German non-governmental medical–scientific charity organization, started several long-term aid programmes and treatment and research projects on thyroid cancer and other diseases of this organ. Since 1993, the project “Thyroid Center Gomel” had more than 70 000 patients from this region for the diagnosis and treatment of thyroid diseases including cancer. The project of the “Pathological Anatomical Laboratory” is situated in the Oncological Dispensary in Minsk, where all childhood and juvenile and many adult thyroid cancers of Belarus are operated. More than 6500 thyroid tumours were diagnosed, preparing over 30 000 pathological slides. In 1997, the project of “Radioiodine Therapy” started in Gomel, giving treatment to more than 450 patients since that time. Since 1992, a fruitful international scientific cooperation on the pathology and molecular genetics of thyroid cancer resulted in a considerable progress in the understanding of this disease and in the installation of a tumour tissue bank.

Radiogenic thyroid cancer in Belarus: fact or fiction?

According to a report published in 1992, the number of thyroid cancer cases in children in Belarus has increased more than 10-fold overall and more than 20-fold in some areas. The increase started in 1990, 4 years after the Chernobyl catastrophe. The histological diagnosis of the cases has been verified by pathologists from western Europe. The report has met with great scepticism in the scientific community. Our intention is to comment on the criticisms made of the report.

Thyroid cancer in Belarus post-Chernobyl: improved detection or increased incidence?

There is debate on whether the reported increase in the number of cases of childhood thyroid cancer in Belarus is real and attributable to radiation released following the Chernobyl nuclear accident, or rather an artefact due to incorrect histological diagnosis, more complete case reporting and mass screening of children after the accident. We have scrutinised the histological slides of 120 (75%) of the 160 cases reported among children aged up to 15 years to the Belarus tumour registry from 1986 to 1992 and examined time trends and geographical patterns in incidence and tumour characteristics. Incidence based on reported cases increased from 0.041 per 100,000 in 1986 to 2.548 in 1992. Carcinoma was confirmed in 94% of reviewed tumours. Except for one medullary carcinoma all histologies were of the papillary type. Most of the tumours had spread beyond the organ capsule and measured over 10 mm in diameter. There was a weak and statistically non-significant trend (p = 0.19) towards smaller tumours in the later years. The proportion of cases with lymphnode or distant metastasis remained unchanged. Incidence based on histologically confirmed cases was highest adjacent and to the west and north of Chernobyl, matching best estimates of iodine-131 contamination. Our data thus strongly suggest that the observed increase is real but more data are needed in order to assess the impact of mass screening and to clarify the possible association with radiation released at Chernobyl in 1986.

No Breathing Room: The Aftermath of Chernobyl

American Ground Zero: The Secret Nuclear War , by Carole Gallagher, 425 pp, with illus, $50, ISBN 0-262-07146-0, Cambridge, Mass, MIT Press, 1993. It is now seven years since the explosion of the Chernobyl nuclear power plant in north central Ukraine. In the past year reports to the journal Nature have confirmed an increase in thyroid cancer in Belarus, where 70% of the Chernobyl fallout was deposited. Studies sponsored by the World Health Organization have begun to track the cleanup workers, who were exposed to some of the highest radiation doses. Documentation of adverse health effects in these and other exposed populations will require decades of careful follow-up. Civilian nuclear power has been far safer in the United States, but nuclear weapons production and testing have extensively contaminated soil and groundwater, particularly in the states of Nevada, Utah, Washington, Colorado, South Carolina, and Ohio. Two new books examine how government secrecy