Thyroid Cancer Rise Linked To Fukushima Radiation
Four Japanese researchers have attributed most of the thyroid cancer cases found among children and adolescents after the March 2011 nuclear power plant crisis in Fukushima Prefecture to radiation from the accident in their report published Tuesday.
Annual thyroid cancer incidence rates in Fukushima after the disaster through late last year were 20- to 50-fold higher than a pre-accident level for the whole of Japan, a team led by Toshihide Tsuda, professor of environmental epidemiology at Okayama University, said in the electronic edition of the journal of the International Society for Environmental Epidemiology.
The finding, based on screening some 370,000 Fukushima residents aged 18 or younger at the time of the accident, “is unlikely to be explained by a screening surge,” the researchers said, pointing to radiation exposure as a factor behind the rise in thyroid cancer cases.
But their conclusion is refuted by other epidemiology experts, including Shoichiro Tsugane of the National Cancer Center, who said the results of the researchers’ analysis are premature.
“Unless radiation exposure data are checked, any specific relationship between a cancer incidence and radiation cannot be identified,” said Tsugane, director of the Research Center for Cancer Prevention and Screening. He also referred to a global trend of overdiagnosis of thyroid cancer.
As of late August, the Fukushima prefecture government identified 104 thyroid cancer cases in the prefecture.
But the prefectural government and many experts have doubted whether these cases are related to the nuclear disaster because the radioactive iodine released from the crisis was smaller compared with the level following the 1986 Chernobyl nuclear accident.