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Fukushima Child Thyroid Cancer Issue

Fukushima Child Thyroid Cancer Issue (updated)

(The following are the facts with Fukushima Prefecture’s child thyroid anomalies. It is a synopsis of reports posted in Fukushima Updates and Fukushima Commentary on this website between March, 2011 and January, 2014. Updates of through 3/7/16 are posted at the end. The record shows the reported thyroid cancers with Fukushima Children have nothing to do with the nuclear accident.)
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, May 20, 2014 - The number of children diagnosed with cancerous growths in their thyroids increased to fifty. More than 290,000 children have been screened, to date, and another 70,000 are going to be tested by the end of 2014. 8. Since it is unlikely that any of the detected cancers are due to the Fukushima accident (see above), it is likely that the detailed screening program has been a benefit to the families of the affected children. Without this groundbreaking program, it is likely that none of the cancers would have been found.
Update, October 9, 2014 - New American contributor Rebecca Terrell says “Fukushima’s children aren’t dying”. (9) Terrell is a Practical Nurse specializing in Alzheimer’s and dementia, and an Associate Member of Scientists for Accurate Radiation Information. In her report, she uses a considerable amount of scientific evidence to reject sensationalist claims of a child thyroid cancer epidemic in Fukushima Prefecture. Terrell explains that the Fukushima child thyroid investigation is unparalleled in Japan, and the seemingly-alarming results are most likely due to it being the first study of its kind. In fact, she points to three other parallel studies in Japan, far from Fukushima, which reveal that the rate of Fukushima thyroid cysts and nodules is the lowest of the bunch. Terrell adds that the discovery of Fukushima Prefecture likely having he lowest rate of thyroid anomalies had virtually no Press coverage outside of Japan, which she says is “understandable since drama-seeking sensationalists have no nuclear power plants to blame.” [aside – We saw only two reports from inside Japan when the data from the three non-Fukushima prefectures was released. – end aside] In addition, Terrell also points to a Wall Street Journal blog that shows the rate of these anomalies in Okuma, one of F. Daiichi’s host communities, is no different than with Inawashiro, which is a hundred kilometers distant. If the nuke accident releases were actually causing thyroid anomalies in children, the occurrence nearest the damaged plant should be significantly higher than that happening far away. Much of Terrell’s report summarizes the work of prominent radiation biologists and other reputable researchers who have taken issue with the “no-safe-level” notion (a.k.a. Linear/No Threshold) continually promulgated in the Press and by nuclear-critical writers. She explains the historical sources of this flawed, unscientific assumption, and that large populations world-wide receive exposures many times greater than the limits mandated in Japan without negative health problems. Terrell concludes, “Anti-nuclear activists and nuclear disarmament proponents cling to the discredited hypothesis [LNT], sacrificing lives and economies for the sake of an imprudent political agenda.” Though lengthy, I highly recommend taking the time to read this report in its entirety.

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.

Update October 29, 2015 - Fukushima University’s Dr. Shinichi Suzuki presented his team’s screening results covering nearly 450,000 individuals following the nuclear accident in 2011 at the 15th International Thyroid Congress and 85th Annual Meeting of the American Thyroid association in Lake Buena Vista, Florida. His report was directed at the recent interest coverage concerning a Japanese researcher’s study claiming the increased child thyroid cancer rates in Fukushima are due to the nuke accident’s I-131 releases. Suzuki says the data does not support the new claim because the confirmed cancers thus far “appear to have occurred prior to [Fukushima] radiation exposure”. Further, the average size of the suspect thyroid tumors were significantly smaller with the post-accident screening cohort than had been the case with those screened before the Fukushima releases happened in March, 2011 (1.4cm vs. 4.1cm, respectively). Plus, the average age of those from the post-accident cohort having surgery was much older than those recorded in pre-accident screenings (17.4 years vs. 11.9 years, respectively). If the tumors found post-accident were due to Fukushima radiation, the average age of the surgery patients should have been much, much lower. Ironically, Suzuki’s findings were supported by another Japanese specialist who made a plenary lecture comparing Fukushima to Chernobyl. Dr. Nagataki of Nagasaki University, the Radiation Effects Research Foundation in Hiroshima, and the Radiation Effects Association in Tokyo, said, “We were surprised to see so many children with thyroid cancer . We found a huge number of children [with thyroid cancer] by screening but […patient] ages were very different [from Chernobyl].” He added that “We did not find regional differences in the prevalence of thyroid cancer within Fukushima Prefecture” which should have been the case due to the wide range of contamination levels across the region.

Update 12/17/15 - Fukushima Prefecture released their child thyroid screening data for 2014-15. There were nearly 153,000 children screened in 2014 from the 25 municipalities with the highest measured I-131 depositions. In 2015, another 47,000 were screened in the 34 remaining municipalities. In 2014, 41.7% of those screened had no detectible nodules or cysts, and 57.5% did. In 2015, 38% showed no detectible nodules or cysts, and 62% did. 1,200 had >5mm nodules requiring follow-up testing for possible cancer in 2014, and 270 in 2015.  There were two cysts of greater than 20mm each year. Of the total of 2015 anomalies, 39 were judged to be either “suspicious or malignant”, all but one of which occurred in 2014. Fifteen of these tested positive for papillary thyroid carcinoma and were surgically removed. The screenings were not only offered in Fukushima Prefecture. More than 10,000 were performed in 46 other prefectures where former Fukushima residents now reside.

(Update 3/7/15) - Science Magazine has posted an overview on the Fukushima child thyroid issue. It says the apparently large number of thyroid anomalies detected since the nuke accident, is not unusual for Japan, in general. Using state-of-the-art ultrasound, researchers are finding the rate of anomalies with Fukushima children is not demonstrably different from the rest of the country. T Science also notes that a similar upsurge in the rate of detected anomalies occurred in South Korea 15 years ago, after the use of then-new ultrasound detection was used to screen patients. Seiji Yasumura, vice director of the Fukushima Prefecture Health Management Survey, says the upsurge in detected anomalies is not something to get upset about, but “finding small lesions causes patients anxiety.” He laments that it has caused over-reaction, resulting in Fukushima children having their thyroids surgically removed. Yasumura feels that “careful observation” would have been the better option.


1 - Fukushima Children’s Thyroid Examination: How Shunichi Yamashita would like doctors to deal with the results;

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4 - Most Patients Survive Common Thyroid Cancer Regardless of Treatment;

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11 - (The report on the studies done in the three non-Fukushima prefectures)