Thyroid Examination: Remarks on the Results of the Initial Screening

Thyroid cancers found so far through the Thyroid Examination being conducted in Fukushima Prefecture are considered to be unrelated to the radiation discharged due to the accident at Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi NPS.

This evaluation is based on a comprehensive judgment of the following facts:

(i) Exposure doses due to the accident at the Fukushima Daiichi NPS were generally lower compared with those caused by the Chernobyl accident.

(ii) The period of time from the exposure to the detection of cancers is short, mostly from one to four years.

(iii) Cancers have not been detected in those who were 5 years old or younger at the time of the accident.

(iv) Age distribution of patients significantly differs in Fukushima Prefecture and Chernobyl (p.132 of Vol. 1, "Comparison between the Chernobyl Accident and the Accident at Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi NPS (Ages at the Time of Radiation Exposure)").

(v) There are no significant differences in detection rates among different regions.

However, it is necessary to monitor developments over a long term to ascertain radiation effects, so the Thyroid Examination program should continue.

• Included in this reference material on March 31, 2015
• Updated on March 31, 2017