A doctor administers an ultrasound scan on a child to look for evidence of thyroid cancer in this file photo taken at a clinic in the village of Hirata, Fukushima Prefecture, on Feb. 23, 2016. (Mainichi/Junichi Sasaki)

FUKUSHIMA -- A prefectural panel of experts here concluded on June 3 that thyroid cancer diagnosed in a second round of prefecture-wide checks in fiscal 2014 and 2015 on people who were aged 18 and under at the time of the meltdowns at the Fukushima Daiichi Nuclear Power Station in March 2011 was unrelated to their exposure to radiation emanating from the disaster.

The panel is tasked with evaluating thyroid examinations conducted by the prefectural government as part of post-disaster health checkups on residents in Fukushima Prefecture, in the Tohoku region northeast of Tokyo. According to their results, the rate of thyroid cancer discovery was higher among children who were living closer to the nuclear plant at the time of the meltdowns. But when taking into consideration factors including age at examination, there was no correlation between high radiation exposure doses and an increase in chances of cancer discovery.

However, as individual exposure doses were not measured and there is no data on those who have yet to be examined, panel members emphasized that its conclusions are provisional. Gen Suzuki, the head of the panel, said, "We haven't concluded that there are no long-term effects from radiation." He pointed to the need to continue thyroid cancer screenings for the time being while informing the children and their guardians of the demerits of overdiagnosis.

Following fine adjustments to the content of the report, its conclusions will be presented to an executive examination committee.

The second round of screenings, held in the fourth and fifth years after the onset of the nuclear disaster, is essential for judging the potential effects of the nuclear disaster and were carried out on some 380,000 people. Of those, 71 people were suspected to have some form of the cancer, with at least 52 of them receiving operations for the condition.

(Japanese original by Ryusuke Takahashi, Fukushima Bureau)