Fukushima Child Thyroid Cancer Issue (updated)

On October 8, 2011, Fukushima University doctors began checking the thyroids of children in Fukushima Prefecture. The examinations, on a scale that medical officials called unprecedented, came amid concern that the cancer rate among Fukushima Prefecture’s children could surge due to the Fukushima nuclear accident. Dr. Shinichi Suzuki of the university’s medical school predicted it would take several years to carry out preliminary examinations because of the large number of those 18 and under, and the voluntary nature of the study. Suzuki said it would take several years for any irregularities in the children’s thyroids to manifest as cancer. He pointed to the fact that an increase was seen four-to-six years after the 1986 Chernobyl meltdown in Ukraine, but not before. In the international news media, a few critics contended that a longer period of latency should be considered before drawing firm conclusions because of a controversy concerning the biological effects of low level radiation exposure.

For more than a year, the prefectural government offered free thyroid medical exams to the parents of 360,000 children in Fukushima Prefecture. Of the more than 38,000 children tested through March of 2012, 13,646 were found to have thyroid lumps or cysts by the prefectural medical staff. However, the existence of these thyroid anomalies could not be compared to other Japanese children who lived far away from Fukushima because no such data existed. Thus, researchers could not determine if the large number of positive tests was due to the Fukushima accident. Medical researchers planned to conduct similar extensive thyroid examinations on roughly 4,500 children aged 18 or younger, far away from Fukushima Prefecture, in order to make a statistical comparison. Benign thyroid anomalies are not uncommon in children. But, the Japanese government had no epidemiological data-base to make a valid appraisal of the impact of a nuclear accident on child thyroids.

Immediately after these numbers were made public, the antinuclear voices of doom said the data from Fukushima Prefecture was the onset of a cancer epidemic in Japan. Long-standing nuclear energy critic Helen Caldicott, a licensed Australian pediatrician living in the United States, maintained that all positively-detected children should be immediately biopsied because 13,766 of 38,114 children tested, or 36.1%, having either nodules or cysts was alarmingly high. She further insisted that this was an early appearance of thyroid abnormalities, strongly indicating that the children received a very high dose of radiation, and not the very low exposures publicized by the Japanese officials. She also asserted that it is not normal for children to have these nodules and/or cysts. However, Japanese medical experts lacking Caldicott’s extreme antinuclear agenda, scoffed at her statements. Doctors Suzuki and Shunichi Yamashita of Fukushima University posted a formal letter on the Web which concluded, “We have defined what needs the second-stage examination as nodules over 5.1 mm and cysts (non-solid but colloidal or liquid collection only) over 20.1 mm.  Thus, in addition to those with no abnormal findings, those with nodules smaller than 5 mm or cysts smaller than 20 mm have been decided not to be the subjects of further testing such as biopsies, or treatments.” ^1. Thus, less than 0.6% of the Fukushima children who tested positive for these anomalies were medically worthy of further study and/or biopsy. The overlying tone of caution in the Fukushima researcher’s letter was due to their lack of national data which could be used to draw a confident conclusion.

On August 20, 2013, the Fukushima researchers announced discovery of 18 papillary child thyroid cancers. This was out of the 210,000 children which had been tested across the prefecture, up to that point in time. In addition to the 18 confirmed cases, another 25 were suspected of possibly developing the cancer. The national incidence of thyroid cancers across all age groups was said to be “one in hundreds of thousands”, but the data was sparse and lacking a high degree of confidence. For example in 2006, 46 cases of thyroid cancer were officially confirmed in Japan across all age groups, but there was no data on papillary child thyroid cancers in the statistical cohort. Fukushima’s medical team said they could not determine whether or not the 18 cancers were caused by Fukushima radioactive releases. Though unlikely, they could not say it was absolutely impossible. ^2. However, the medical team again stressed that examinations of this sensitivity and detail had never been run on a population of Japanese children this large before, so there was no relevant data in Japan with which to compare the results.

On November 14, 2013, Fukushima’s unprecedented child thyroid survey had found a few more cancers. Of the 226,000 children that had been screened, 26 child thyroids were found to be cancerous and another 32 are felt to be possible thyroid cancer cases. All 26 of the confirmed children underwent successful cancerous material removal surgery and were doing well. The Prefecture’s experts pointed out that papillary thyroid cancer develops at a very slow pace and not enough time has passed to link the newly discovered cancers to the Fukushima accident. Fukushima’s screening program had never occurred before in Japan, thus there is no way to assess whether or not the number of cases is typical. ^3. In addition, there was scientific evidence that papillary thyroid cancers are more common than data might suggest. ^4. In fact, the referenced report states, “Studies published as early as 1947 demonstrated it [the commonality of papillary child thyroid cancer], and more recently, a report has shown that nearly every thyroid gland might be found to have a cancer if examined closely enough.” Thus, scientific evidence on the specific thyroid cancer found in the Fukushima cohort added further intensity to the desire for a more substantial data base using prefectures far from Fukushima.

Many Japanese Medical experts said these frequencies were probably not unusual for Japan when the extreme sensitivity of the survey and type of cancer was considered. They pointed to similar screenings which were run in three far-distant Prefectures in 2012 and early 2013, the numbers of which were publically posted. Results showed that the Fukushima child thyroid cancer frequencies were relatively consistent with the other three Prefectures. In fact, the other three Prefectures had child thyroid anomaly rates slightly higher than with Fukushima. ^5. The three tested prefectures, far from Fukushima, were Nagasaki, Aomori and Yamanashi. While the percentage of Fukushima children with detectible nodules/cysts was 41.2%, the combined percentage found in the other three prefectures was 56.6%! Further, while 0.6% of the Fukushima children with the anomalies were considered worthy of further testing, the other three prefectures had a rate of over 1%. The total number of children tested in the far-from-Fukushima prefectures was 4,300, thus the data was considered scientifically and statistically valid. One over-riding conclusion was drawn out of this study: It seemed the child thyroid anomalies first detected in Fukushima Prefecture had been occurring quite normally across the entire country, but had gone largely unnoticed before the national screenings of 2102-13. But, the bottom line was that the Fukushima data was in no way indicative anything unusual.

However, that’s not what many radiation-averse people in Japan wanted to hear. Millions of Japanese wanted to believe the bad news and rumors concerning the child thyroid situation in Fukushima, and disbelieved any posted evidence to the contrary. Many concluded either that all of Japan was so heavily contaminated by the Fukushima nuclear accident that children outside Fukushima have even higher incidents of thyroid abnormalities, or that the Fukushima researchers were doctoring the statistics. Thus, even the most conclusive evidence concerning child thyroid issues with respect to Fukushima, and all of Japan, was rejected by a numerically-significant fraction of Japan’s population because it contradicted their pre-existing mind-set.

Finally, it was reported on December 23, 2013, that there were 59 cases of child thyroid cancers either confirmed or suspected. A few medical critics remained convinced it was possible that the number of child thyroid cancers in Fukushima Prefecture may have been due to nuke accident exposure, clinging ruthlessly to a comparison with national registry data. One dissenter, Okayama University professor Toshihide Tsuda, purported that the frequency of child thyroid problems in Fukushima Prefecture is “several tens of times” higher than before the accident. He said national statistics between 1975 and 2008 showed a variance of between 5 to 11 cases per million people. Tsuda concluded that 59 cases out of ~240,000 Fukushima children is so much higher than national registry data, that the possibility of Fukushima radiation as a cause cannot be dismissed. However, most medical experts said that Tsuda’s conclusion was non-scientific because it was based on national statistics covering all age groups and should not have been compared to the 18-and-under cohort alone. Tetsuya Ohira of Fukushima Medical School said it is not scientifically appropriate to compare the Fukushima child numbers with the national cancer registry. Another Fukushima Medical University professor Shinichi Suzuki said there is no actual link between the low nuclear accident radiation exposures and the confirmed/suspected child thyroid cancer cases in Fukushima. The expert opinions were presented at a December 21, 2013, meeting held by Tokyo’s Environment Ministry and the Fukushima government. ^6.

By the end of December, 2013, the consensus of Fukushima medical experts were agreed that the apparently-elevated child thyroid cancer rate in the prefecture was probably not due to the accident. Generally, they said it was too soon to judge that Fukushima radiation was the culprit and the new national data seemed to confirm their opinion. They continued to stress it was unlikely that the cancers are due to the nuke accident because of the fact that Chernobyl thyroid anomalies did not happen until 4-6 years after the accident, and it had been less than three years since the atmospheric release of radioactive Iodine from Fukushima. Plus, the amount of radioactive Iodine expunged into the environment from F. Daiichi was many times less than with Chernobyl. Further, severe food consumption restrictions were imposed in Japan that were not the case in the Ukraine. Thus, the worst-case child exposures from Fukushima were many, many times less than what occurred with Chernobyl. Dr. Choi Kin of Hong Kong Medical Association added that no one can scientifically prove the increase in cancer incidence was from Fukushima, and that other natural causes were most likely the root-cause of the issue. ^7.

Update 11/30/14 – Fukushima Medical School Professor Shinichi Suzuki said the reported Fukushima child thyroid cancers differ genetically from Chernobyl’s. 23 of the 103 confirmed thyroid cancer cases underwent additional genetic analysis. The study focused on gene variations in cancer cells. Discovered mutations were the same as those commonly found in Japanese adult thyroid cases. However, there was no similarity to mutations linked with the 1986 Chernobyl accident. In fact, the type of gene variations commonly found among the Chernobyl cases was not detected among any of the 23 analyzed Fukushima cases. Thus, it is highly unlikely that the child thyroid cases specific to post 3/11/11 Fukushima children are due to the nuclear accident releases. ⁽¹⁰⁾

 

Update June 1, 2015 – Ushiku City of Ibaraki Prefecture announced their latest child thyroid data. 48 of 89 children were given either an A2 or B diagnosis. A2 designates detectible thyroid anomalies of less than 5 millimeters for nodules and/or <20mm for cysts. The B diagnosis is for nodules >5mm and cysts >20mm. 40 of the Ibaraki children were found to have A2 anomalies and 8 with B level. Those diagnosed A2 will be monitored for future changes, and the B children studied for possible cancer. Thus, the rate of anomalies for this small cohort was about 54%, which compares favorably with rates found in Nagasaki, Aomori and Yamanashi Prefectures since 2012 (56%). Ushiku City is about 200 kilometers southwest of F. Daiichi. The rate for Fukushima Prefecture is about 42%. This further indicates that there is no actual child thyroid cancer outbreak from the Fukushima accident.