There was a report in Evacuate Fukushima about thyroid cancer in young people:
By February 2014, a whooping 75 children out of roughly 270 000 are either confirmed or suspected to have contracted the disease. Toshihide Tsuda, a professor of epidemiology at Okayama University: “The rate at which children in Fukushima Prefecture have developed thyroid cancer can be called frequent because it is several times to several tens of times higher” [Based on Japan’s cancer registration statistics from 1975-2008 which show an annual average of 5-11 people in their late teens/early 20s developed thyroid cancer for every 1 million people] “Because there is the possibility that the number of cases could increase in the future, there is a need to implement measures now.”
Seventy-five per quarter million works out to about 300 per million. Registry data shows one should predict about 10 per million. The observed rate is then 30 times normal. These findings are just three years after the event. The rate is likely to climb for years.