The second follow-up survey of the 2011 Fukushima disaster has thrown up more diagnoses of children with thyroid cancer. Since April 2014, 16 children have been confirmed to have the condition, as well as 35 suspected cases, all aged between six and 18-years-old.
This is a rise from the previous survey, which ran from March 2011 to March 2014, which showed 15 confirmed diagnoses of thyroid cancer in children, with 24 unconfirmed reports. The Fukushima Prefectural government announced on 15 February that the latest figures have given rise to a total of 116 cases of thyroid cancer since the disaster, according to Japan Today.
The survey followed the health of 380,000 children and young adults under the age of 18. All of them were living in the northeast of Japan in March 2011 – when the Fukushima nuclear disaster occurred.
A combined 51 children had either been diagnosed with thyroid cancer or suspected of having it. The doctors say their tumours ranged from just over 5mm, to the size of an Olympic hockey ball.
Researchers managed to pinpoint the amount of radiation these children had received in the four months before the nuclear disaster. While ten received less than one millisievert, the maximum was 2.1 millisieverts – the equivalent of working the entire time in an Australian uranium mine.
The results showed that five of the 16 new confirmed cases have appeared since December 2015, when Hokuto Hoshi – senior member of the Fukushima Medical Association – downplayed the link between thyroid cancer and the nuclear disaster.
"As far as our data shows, the estimated internal doses of radiation of Fukushima residents for thyroid glands are lower than those of residents around the Chernobyl nuclear plant," Hoshi said at the time. "It is unlikely that radiation is responsible for the recently reported thyroid cancer cases, given that there are no reports of cancer among infants, who are particularly susceptible to radiation."
The annual thyroid cancer rates in the immediate area surrounding Fukushima since the 2011 disaster is roughly 20 to 50 times higher than the national level.