15 November 2014
A pathological study on the thyroid gland based on a health survey of some 370,000 people aged 18 or younger in Fukushima Prefecture suggests that thyroid cancer cases among them are unlikely to be linked to exposure to radiation from the 2011 reactor accident at the Fukushima Daiichi nuclear power plant of Tokyo Electric Power Co. The health checkup was undertaken by the prefectural government and Fukushima Medical University following the accident. The results of the survey were analyzed jointly by a team of experts from the university and Nagasaki University.
The thyroid study was focused on gene variations in cancer cells. It found that the type of such mutations among Fukushima youths was different from that among children who developed thyroid cancer after the Chernobyl nuclear disaster of 1986. This led the team to conclude it is not likely that the Fukushima accident has had any effect on the thyroid cancer cases found in the survey.
The finding was reported on Nov. 14 by Shinichi Suzuki, professor of thyroid endocrinology at the Fukushima medical school, during an academic gathering of the Japan Thyroid Association in Osaka. The health survey found 103 confirmed or suspected thyroid cancer cases. Earlier, the prefectural government and the university had said radiation from the accident is unlikely to have had any link to the disease given scientific knowledge such as its prevalence. The latest gene-level analysis has given credence to the view.
According to the report, 23 of the 103 cases confirmed as thyroid cancer were subjected to genetic analysis. Most gene mutations found in cells of these confirmed cases were of the type that is commonly seen in thyroid cancer among adults in Japan and that was not found among children with thyroid cancer developed after the Chernobyl accident. Furthermore, the type of gene variations commonly found among the Chernobyl cases was not detected among any of the 23 Fukushima cases.
(Translated by Kyodo News)