SUPPORT FOR THYROID CANCER AND OTHER THYROID DISEASES IN BELARUS

该合同是为了继续进行“白俄罗斯甲状腺癌和其他甲状腺疾病研究”，这是一项大规模的流行病学研究，检测受到1986年4月26日切尔诺贝利核电站事故释放的辐射的人的甲状腺和其他病理。该研究涉及两个队列：(1)“主要队列”建立于20世纪90年代末，由11,732名受试者组成，这些受试者在事故发生时年龄在18岁或以下，接受了甲状腺剂量测量，居住在白俄罗斯切尔诺贝利受影响地区；(2) 2017年建立的“子宫内队列”，由2965名在子宫和产后早期生活中暴露于切尔诺贝利沉降物辐射的人组成。该合同的主要重点是对最近建立的子宫内队列进行甲状腺癌和疾病的医学筛查。主要队列在经历了三个周期的甲状腺筛查后，过渡到基于联系的被动随访。

The contract is for the continuation of the “Study of Thyroid Cancer and Other Thyroid Diseases in Belarus”, a large-scale epidemiological study detecting thyroid and other pathology in persons who have been exposed to radiation as released by the accident at the Chernobyl Nuclear Power Station in April 26, 1986. The study involves two cohorts: (1) the “main cohort” that was established in the late 1990s and consists of 11,732 subjects who were age 18 or under at the time of the accident, had their dose to the thyroid gland measured, and lived in the Chernobyl affected areas in Belarus; and (2) the “in utero cohort” that was established in 2017 and consists of 2.965 persons who were exposed to Chernobyl fallout radiation in utero and early post-natal life. The main emphasis of this contract is to conduct medical screening for thyroid cancer and diseases in the recently established in-utero cohort. The main cohort, after having undergone three cycles of thyroid screening, transitioned to linkage-based passive follow-up. The specific objectives are: for the in utero cohort, (1) to conduct medical screening for thyroid cancer and thyroid non-cancer disease; (2) to evaluate the reliability of questionnaire-based doses previously reconstructed; for both the main and in utero cohorts: (3) to maintain passive follow-up to update occurrences of thyroid cancer, other cancer and thyroid non-cancer disease, through linkage with the Chernobyl State Registry and the National Belarusian Cancer Registry, (4) update demographic, clinical and epidemiologic data through a mail survey. Medical screening of in utero cohort focuses on thyroid cancer but also ascertain a wide spectrum of benign lesions, including benign tumors, nodules, functional changes (hyper- or hypothyroidism, thyroiditis, etc.), which have been associated with radioiodine exposure. Another important aspect of the study is the evaluation of uncertainty of questionnaire-based doses due to memory recall. NCI’s previous study shows that if dose-related measurements are available for study subjects, the quality of individual behavior and dietary data has, in general, a small influence on the results of the retrospective dose assessment. However, direct thyroid measurements are available only for around 15% of mothers of in utero cohort subjects; evaluation of uncertainty in doses due to possibly poor memory recall is important for this study. Another task for the contract is to update the dataset for the main and in-utero cohort with information obtained as a result of record linkage to the State Chernobyl Registry and National Belarusian Cancer Registry. We are also updating vital status and last known address for the subjects of main cohort through a mail survey.