Reconstruction of individual thyroid doses to the Ukrainian subjects enrolled in the Chernobyl Tissue Bank

Abstract

The Chernobyl Tissue Bank (CTB) is an organisation that collects and stores samples of tumoral thyroid tissue obtained from Ukrainian and Russian subjects who were treated surgically for a thyroid cancer and had been exposed to (131)I from the Chernobyl accident. By 2012, the CTB had collected specimens of thyroid tissue from 2267 residents of Ukraine for the purpose of radiation research. Arithmetic mean thyroid doses and uncertainties have been estimated for all but 24 subjects for whom residence at the time of exposure was not found. The subjects have been classified into six groups or sub-groups according to the type of dosimetry-related information that is available for each of them. Excluding the 325 subjects with negligible radiation exposure, the arithmetic mean of the thyroid dose over all subjects is estimated as 0.4 Gy, with individual values ranging from <1 mGy to 13 Gy. The uncertainties in the individual thyroid dose estimates, characterised by the geometric standard deviations of their probability distributions, range from 1.3 to 8.7, with an arithmetic mean of 3.2.

Gene signature of the post-Chernobyl papillary thyroid cancer

“…However in our study the place of residence of patients in the ECR and non-ECR groups were evenly distributed within different regions (oblast) and we consider that in a retrospective series cases this is the best available method to control for differences in iodine dietary status. Unlike other authors [ 18 , 20 ], we did not show formal analysis of gene expression in relation to individual radiation doses provided by the CTB [ 35 ]. Although the Spearman’s dose–response correlation indicated a few significant genes (data not shown), due to uncertainty in radiation dose and possible inclusion of patients with sporadic PTC in the non-ECR group, we consider these data too biased.…”

Dose-dependent expression of CLIP2 in post-Chernobyl papillary thyroid carcinomas

“…In the present study we used the same dose estimates for the UkrAm cohort as Brenner et al ( 6 ). For the Genrisk-T cohort dose estimates were published by Likhtarov et al ( 27 ) and provided by the CTB.…”

Comparative Histopathologic Analysis of “Radiogenic” and “Sporadic” Papillary Thyroid Carcinoma: Patients Born Before and After the Chernobyl Accident

“…The study included 495 Ukrainian PTC cases selected among 3991 PTCs operated at IEM between 1990 and 2015, when a significant rise in thyroid cancer incidence was registered in Ukraine. Considering that the highest risk of thyroid cancer following the Chernobyl accident was observed in the youngest children residing in the most contaminated regions (6)(7)(8)(9)(10)(11), the radiogenic cases were defined as those who were four years old or younger in 1986 and who lived in the Kiev, Chernihiv, or Zhytomyr regions. The comparison group included sporadic PTC cases selected among those who were born after the accident ( January 1, 1987, or later and not exposed to 131 I) and lived in the same regions as the radiogenic cases or Kiev city.…”

“…The incidence of thyroid cancer in Ukraine has been shown to be substantially higher in six northern regions closest to the CNPP site, and particularly in three of those-Kiev, Zhytomyr, and Chernihiv-which were the regions most contaminated by radioactive iodine ( 131 I). The highest 131 I dose-dependent excess in incidence was observed in children whose age in 1986 was four years or younger (6)(7)(8)(9)(10)(11).…”