2021 Volume 58 Issue 5 Pages 340-345
The Fukushima Daiichi Nuclear Power Plant Accident that followed the Great East Japan Earthquake raised concerns about pediatric thyroid cancers, which occurred after the Chernobyl Accident. Therefore, the Fukushima Prefectural Health Survey “Thyroid Ultrasound Examination” (TUE) was started about seven months after the earthquake. TUE consisted of a primary examination with thyroid ultrasonography and a confirmatory examination for those who were found to have thyroid nodules of 5.1 mm or larger or cysts of 20.1 mm or larger. The “Preliminary Baseline Survey”, which was the first-round survey, was conducted during the period considered to be the latent period for the development of thyroid cancer after radiation exposure, and the “Full-Scale Survey”, which is conducted every two years, started in FY2014. Evaluations up to the second-round survey showed that thyroid cancer that developed during these rounds of survey was not considered to be the effects of radiation. Currently, the fifth-round survey, which started in FY2020, is being conducted. The risk of thyroid cancer is often very low, and thyroid cancer in children and young adults is generally considered to have a good prognosis. However, knowledge about the natural history of thyroid cancer is lesser in children than in adults, and a more careful management is required depending on the risk level. In this study, thyroid nodules were examined according to the guidelines of relevant Japanese medical societies, and 260 cases were diagnosed as malignant or suspicious for malignancy on the basis of cytological diagnostic findings as of the end of FY2020. In this article, we report the progress and current issues of TUE and review findings on pediatric thyroid cancers found in Fukushima.
