Childhood Thyroid Cancer Rate: Fukushima compared with the USA

Kyodo News reports today that there are now 12 confirmed cases of thyroid cancer in Fukushima Prefecture among persons 18 or younger. Researchers at Fukushima Medical University believe that the cases are not related to the Fukushima catastrophe because after the Chernobyl catastrophe cases emerged only after four or five years.

The report lacks any comparisons or interpretations that could help people understand this situation. I’m not a medical researcher or a professional journalist, but it took me less than thirty minutes to find some statistics that provided valuable perspective on these children in Fukushima who have thyroid cancer.

Anyone can go to the websites of the American National Cancer Institute and look up cancer incidence by age, race, region and various other criteria. If you go to this site and look up the rate of thyroid cancer for people under 20 of Asian ancestry, you find a rate for the year 2009 of 0.9478 per 100,000.

If it is reasonable to assume that most underlying causes of thyroid cancer are the same in Japan and the USA, we would expect the same rate to be found in Japan. I will leave it to the professional, paid reporters of Kyodo and other Japanese media groups to look up the data on Japanese government websites.

The Kyodo report says 174,000 people 18 or under were included in the survey looking for thyroid cancer. According to the American data, we would expect to see one or two cases of thyroid cancer in this group, not 12 with 15 additional suspected cases. It is difficult to think of a difference between American and Fukushima diet, environment and genetic background that would account for this large increase. The only significant difference between the two places is that one had a nuclear power plant triple meltdown and spent fuel pool melt, and the other did not. If researchers didn’t know about the meltdowns, they would suspect that there had been an undetected exposure to radioactive iodine. The six fold increase just jumps off the chart.

Skeptics will say the raw numbers (2 expected, 12 found) are too small to confirm a statistically significant trend. It could be random variation. If you throw confetti in your room, some floor tiles will have no confetti land on them, some will have two, some will have twelve, etc... The year 2007 and 2013 are just different floor tiles. Furthermore, these 12 cases of cancer can be presented as either a frightening jump in the incidence rate (a six-fold increase!), or they can be portrayed as insignificant (a change from 0.01% to 0.07% of 100,000 people). It is possible that a few cases were found simply because every young person in a population of 174,000 was screened, but to go with that reasoning you would have to believe that a certain number of American children have thyroid cancer but just slip through the system undetected and die with the cause unknown.

Another obvious explanation, which seems to be beyond the powers of imagination of researchers at Fukushima Medical University, is that the Soviet research on Chernobyl was flawed. Researchers there may have simply missed the early cases or deliberately avoided looking for them – the well-documented pattern described in Chernobyl: Crime without Punishment. It seems like it is time for Japanese authorities to wake from their complacency and admit the possibility that something dreadful has happened to the children of Fukushima Prefecture, something that would justify large damage rewards for everyone who gets thyroid cancer from now on.

NOTE: A few days after I wrote this post Asahi Shimbun came through with some figures on thyroid cancer rates in Japanese children before 2011. In 2007, Miyagi Prefecture (neighboring Fukushima) and three other prefectures had a rate of 1.7 per 100,000 children, a little less than twice the rate in the USA.