Dynamic monitoring of nodular goiter in members of the Ukrainian-American thyroid cohort: analysis of the results of 6 cycles of standardized screening

Abstract

In recent decades, studies conducted in different countries of the world have substantiated and implemented protocols for the diagnosis, treatment, and management tactics of nodular pathology of the thyroid gland (TG). At the same time, uncertainties remain questions about the features of observation and tactics of managing patients with nodular goiter with a history of radiation exposure, which can play a significant role in the initiation and development of the thyroid node. The aim — retrospective analysis of long-term follow-up of nodular goiter in individuals exposed to radiation as a result of the accident at the Chernobyl nuclear power plant. Material and methods: among 13,243 people from the areas of radiation control, who, during 1998-2000, underwent the first cycle of the epidemiological cohort examination of the TG within the framework of the joint Ukrainian-American project, «Scientific project for the study of cancer and other diseases of the thyroid gland in Ukraine as a result of the accident at the Chornobyl nuclear power plant»), a group of 366 individuals with identified nodular pathology of the thyroid gland >5 mm in diameter was selected. The age of the subjects at the time of the Chornobyl accident was 0-18 (average age: 8.98±0.23 years) by the time nodal pathology was detected — 13-31 years (mean age: 22.74±0.23 years); among them were 265 women and 101 men. The distribution of thyroid radiation dose was as follows: 197 people (53.8% of the total number) — <0.3 Gy, 95 people (26.0%) — from 0.3 to 1.0 Gy and 74 people (20, 2%) — >1.0 Gy. Screening examinations according to the protocol, which were carried out every 2-3 years from 1998 to 2015, passed: 2nd cycle — 346, 3rd — 330, 4th — 300, 5th — 204 and 6th — 300 people. In the presence of indications, fine-needle aspiration puncture biopsy (FNA) of thyroid nodules was performed, and if necessary, surgical treatment. An analysis of the ultrasound characteristics of thyroid nodules (number, size, localization and type) and the results of laboratory studies of the levels of thyroid-stimulating hormone, free thyroxine, antibodies to thyroperoxidase, antibodies to thyroglobulin was performed. The results. Hormonal studies showed that by the time of detection of nodular goiter in the vast majority of people (90%) thyroid-stimulating hormone level was within the reference values; in 99 people (82%) the level of antibodies to thyroperoxidase did not exceed the norm; 58 people (16%) showed an increase in antibodies to thyroperoxidase; 287 people (78%) had a basal TG level within the normal range. In the future, no significant changes in the hormonal status of the subjects were observed. According to the ultrasound examination, during the first examination cycle, the distribution of thyroid nodules by type was as follows: cystic nodules were detected in 39 people, solid nodules — in 140, and combined ones — in others. 88 patients were operated on in the clinic of the State Institution «V.P. Komisarenko Institute of Endocrinology and Metabolism of the National Academy of Medical Scienses of Ukraine»: 59 women and 29 men. Histological diagnoses were distributed as follows: 24 cases — follicular adenoma, 2 cases — follicular carcinoma, 44 cases — papillary carcinoma, 5 cases — single nodular non-toxic goiter, 5 cases — multi-nodular non-toxic goiter, 3 cases — mixed non-toxic goiter, 2 cases — metastatic lesion of TG, 1 case — recurrent goiter after removal of papillary carcinoma and 1 case — autoimmune thyroiditis. Conclusions: 1. Regular screening examination of members of the Ukrainian-American thyroid cohort under the 1st screening program revealed focal thyroid formations in 366 people, which is 2.8% of all those examined. 2. Dynamic observation of the cohort members with focal formations showed that there was an active transformation of the nodular goiter into a multinodular one. 3. Based on the results of ultrasound and cytological examination, patients with focal formations at the 1st screening were referred for surgical treatment and 43 cases of thyroid carcinomas (papillary — 41 and follicular — 2), 22 cases of follicular adenoma and 11 cases of nodular non-toxic goiter were operated on. 4. Carrying out regular cycles of screening examinations of persons exposed to radiation exposure in childhood and adolescence, with focal formations of the thyroid gland, contributes to the timely detection of benign and malignant tumors of the thyroid gland.