Abstract
Recent studies have confirmed that an increase in the number of patients with papillary thyroid cancer is due to the effects of the Chornobyl accident, and a cohort of persons who lived in the areas being exposed to radioactive contamination in 1986 has an increased risk of thyroid carcinoma even 30 years after the disaster.
The objective of the research was to evaluate the results of treatment as well as to determine an optimal protocol of diagnosis, therapy and monitoring of patients with thyroid papillary carcinoma developed among the population of Ukraine in the period after the Chornobyl disaster.
Materіals and methods. The analysis of treatment of 6,239 patients with papillary thyroid cancer during 1990-2015 was made. Follow-up period lasted from 1 to 25 years after initial surgery, on average 11.8±2.1 years. The age of patients ranged from 7 to 74 years. The mean age was 38.3±7.4 years. There were 5,003 (80.2%) females and 1,236 (19.8%) males.
Results. Papillary thyroid carcinomas of the early period of the accident were characterized by a short latency period, high biological potential of malignancy with high level of invasiveness (extrathyroidal invasion in 51.7%; regional lymphatic metastases in 36.7%; distant metastases to the lungs in 5.2%). Over time, an improvement in the quality of ultrasound and cytological diagnosis allowed increasing the number of surgeries performed at the early stages of carcinoma development (up to 59.8% of cases). All patients underwent surgical treatment: thyroidectomy (84.6%), neck dissection of different lengths (27.8%), hemithyroidectomy in case of low-risk minimally invasive carcinoma (15.4%). In the group of pediatric patients at the time of the Chornobyl accident, the cumulative 15-year survival rate according to Kaplan-Meier method was 98.9%.
Conclusions. In case of preoperative cytologic diagnosis of “thyroid carcinoma” in patients who were children at the time of the Chornobyl accident, it is mandatory to perform total thyroidectomy in combination with preventive central neck dissection (level VI lymph nodes) regardless of the degree of tumor spread. Modified lateral neck dissection is indicated in case of confirmation of metastases. Further ablative radioiodine therapy allows evaluating the effectiveness of treatment according to the level of serum thyroglobulin and antibodies thereto, and early detection and surgical removal of iodine-refractory metastases does not affect survival rates.
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