FINDINGS FROM THYROID EXAMINATION

After the Chernobyl nuclear power plant accident, pediatric thyroid carcinoma has been revealed as a health hazard due to internal exposure to radioactive iodine. With regard to the Fukushima Daiichi nuclear power plant accident, thyroid ultrasonographic examinationhas been conducted in Fukushima prefecture since October 9^th, 2011 on children who lived in Fukushima prefecture and were between the ages of 0 and 18 years old during the earthquake in order to observe their long-term health. At this point, the first examination (hereafter, “preliminary examination”) is almost finished. After that, examinations are planned for once every 2 years until age 20, followed by once every 5 years (hereafter, “core examination”). In addition to describing the results of the preliminary examination, this study provides an opportunity to think together about what has been understood from the examination and how these findings can be applied to health maintenance activities in the future.

First, I would like to describe the overview of the examination and a brief explanation of the thyroid, followed by a description of the examination results. Among approximately 360,000 primary examination subjects, 80.5% have been examined as of June 30^th, 2014. Among them, 2,237 (0.8%) continued to the secondary examination. Among 1,848 participants who underwent the secondary examination, cytodiagnosis was performed in 485 participants. As of June 26th, 2014, 104 participants were diagnosed as malignant or malignant suspect.

There were 36 male and 68 female participants. Among the 104 participants, 58 have undergone surgery so far. One was diagnosed with a benign nodule, 55 with papillary thyroid carcinoma, and 2 with poorly differentiated carcinoma. In addition, the age at secondary examination was 8 years old and older. Furthermore, although secondary examination in Aizu area had not been completed, we examined regional differences on primary and secondary examination within Fukushima prefecture. The diagnosis rate of malignant and malignant suspect was 33.5 per 100,000 people in 13 municipalities. The results were similar in the three areas other than Aizu. Aizu area showed a slightly lower result.

By repeatedly performing the core examination, we plan to observe the thyroids of children and to reflect the obtained results in health maintenance activities within Fukushima prefecture.