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Tuesday, May 19, 2015

Fukushima Thyroid Examination May 2015: 103 Thyroid Cancer Cases Confirmed, 5 in the Second-Round Screening

The Nineteenth Prefectural Oversight Committee for Fukushima Health Management Survey convened in Fukushima City, Fukushima Prefecture, on May 18, 2015, releasing the latest results of thyroid examination, consisting of Initial Screening or the first-round screening (originally scheduled to be conducted from October 2011 to March 2014, but actually still ongoing) and Full-Scale Screening or the second-round screening (beginning April 2014). It has been 3 months since the last committee meeting on February 12, 2015, and the latest results include 3 more months worth of data confirmed as of March 31, 2015.

An official English translation of the results will be available here.

As of March 31, 2015, there are 16 more (12 from the first-round and 4 from the second-round) confirmed cancer cases, all papillary thyroid cancer, and 9 more (2 from the first-round and 7 from the second-round) newly suspicious cases. The number of confirmed cancer cases now totals 103 (98 from the first-round and 5 from the second-round), and 23 more await surgical confirmation. (The number of suspicious/malignant is officially 127, including the single case of post-surgically confirmed benign nodules).

Initial Screening (the first-round screening) targeted about 368,000 individuals who were age 18 and younger, residing in Fukushima Prefecture at the time of the Tokyo Electric Fukushima Daiichi nuclear power plant accident on March 11, 2011. 

Full-Scale Screening (the second-round screening), to be conducted every 2 years until age 20 and every 5 years after age 20, additionally targets those who were born in the first year after the accident, aiming to examine approximately 385,000 individuals in a 2-year period. 

Officials are still accepting first-time subjects in the first-round screening in an attempt to raise the participation rate, allowing those who haven't yet undergone Initial Screening to participate in it so long as they have not received a notification letter for Full-Scale Screening. As a result, 966 more, or 81.5% of the eligible underwent the primary ultrasound examination, either in Fukushima Prefecture or in other prefectures where they have relocated to. This is 0.3% more than the results released on February 12, 2015, and gave rise to the 2 newly suspicious cases. Although no individual information was released, a comparison of the latest results to the previous results from February 2015 reveals that they are both women, one from Iwaki City and the other from Aizu Wakamatsu City, whose ages were 11 and 18 at the time of the accident, and at least one of the two had a tumor diameter of 45.0 mm. 

The second-round screening results include a table showing how the test results changed from the Initial Screening to the Full-Scale Screening. The column called "Non-participants" shows 7,072 subjects who never underwent the first-round screening but went through the second-round screening. It seems more logical to include the above 2 cases in the "Non-participants" category of the second-round screening, rather than in the first-round screening.

It is notable that the number of suspicious/malignant cases in the second-round screening nearly doubled, from 8 to 15, in the three months since the February report. The number of subjects participating in the confirmatory examination increased by about 60%, and the number of confirmed results nearly doubled with the number of biopsy increasing by 150%. So it is in a way not surprising the number of suspicious/malignant cases warranting surgical confirmation increased. Moreover, it is a concern that a little over half of those eligible for the confirmatory examination actually were examined, which means the number of suspicious/malignant cases are projected to increase even more as the progress rate of the confirmatory examination increases.

Again the details of the additional 7 cases newly determined to be suspicious/malignant after biopsy are not specified in detail, but comparison with the previous results reveals they include 2 males (ages 12 and 14 at the time of the accident) and 5 females (ages 8, 14, 17, 17 and 18 at the time of the accident). The average tumor diameter for the suspicious/confirmed cases in the second-round decreased slightly from 10.2 mm to 9.1 mm with the maximum diameter remaining the same, suggesting most newly diagnosed cases had tumor diameters on the smaller end. Their first-round screening results include 3 cases each of A1 and A2, and a case of B. The places of their residence at the time of the accident include the FY 2011 target municipalities of Minamisoma City and Date City and the FY 2012 target municipalities of Fukushima City (4 cases) and Nihonmatsu City. According to the previous results (Jan 2012,  May 2012), most of the Minamisoma City residents had Initial Screening by the end of December 2011, and the Date City residents were screened in Jan-March 2012, whereas Initial Screening began in May 2012 in Fukushima City and in September 2012 in Nihonmatsu City. Although biopsy results were confirmed in these 7 cases sometime between January and March 2015, it is not clear exactly when they underwent the primary examination of the Full-Scale Screening which began in April 2014. Given the limited amount of information, it is not possible to identify where the previously A1 cases lived, who apparently had no ultrasound findings in Initial Screening. It means they likely developed the tumor in a little over 2 years since the last screening, and about 3 years after the accident. 

The Interim Summary of the Thyroid Examination Evaluation Subcommittee meeting, held on March 24, 2015, was reviewed during this committee meeting, as the Subcommittee meeting apparently wrapped up its session as of the March meeting at the end of FY 2014*. The Subcommittee came to a conclusion that the current situation where 99 of 112 suspicious/malignant cases had surgeries and 98 were confirmed with thyroid cancer (95 papillary thyroid cancer and 3 poorly differentiated cancer) clearly represents an excess incidence of pediatric thyroid cancer increased over the Japanese prevalence rate by an order of magnitude (At the November 11, 2014 subcommittee meeting, it was described as "61 times"). Amongst several issues addressed, the interim summary states that this increase can be a result of either excess occurrence due to radiation exposure or over-diagnosis, and that there were opinions amongst the subcommittee members that the current scientific knowledge does not completely deny the former, yet the latter was more likely. It goes on to state, "At the current time, it is not possible to conclude if thyroid cancer cases detected during the screening are radiation-induced. The results of the Initial Screening suggest that it is unlikely these cases are the effect of radiation exposure, considering that the exposure dose is far less than the Chernobyl accident and that there have been no cancer cases in children younger than 5 at the time of the accident. However, a long-term, ongoing study is needed in order to evaluate the effect of radiation exposure. Moreover, the early internal exposure dose from radioactive iodine is extremely critical in assessing the effect of the accident. The screening should continue in conjunction with the dose estimation study. "

Meanwhile, attendees and webcast viewers were surprised to find out that Shinichi Suzuki, a Fukushima Medical University thyroid surgeon who was in charge of the Fukushima Thyroid Examination was replaced with Akira Otsura, an internist and a professor in the Department of Radiation Health Management at Fukushima Medical University. Otsura, formerly of Nagasaki University, was one of the first to go to Fukushima Prefecture immediately after the accident as a head of the radiation medicine team sent from Nagasaki University. Otsura was clearly not knowledgeable about surgical details of the cases as Suzuki was, although a lot of details were not released by Suzuki citing patient confidentiality anyway. During the committee meeting as well as the press conference afterwards, Otsura often did not seem to comprehend questions from other committee members or journalists. There was already an issue of data management and transparency with Suzuki withholding some data from the committee, prioritizing presentations at academic meetings. With the assignment of Otsura and absence of Suzuki at the committee, there appeared to be a setback of information disclosure and transparency.

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A summary of results are provided below for Initial Screening and Full-Scale Screening, followed by unofficial translation of selective tables from the results. All numbers shown below are from the data analysis as of March 31, 2015.

Initial Screening (October 2011 - ongoing)

Total number targeted: 367,685
Number of participants in primary examination: 299,543
Number with confirmed results: 299,233
  • A1   154,018 (51.5%) (no nodules or cysts found)
  • A2   142,936 (47.8%) (nodules ≦ 5.0 mm or cysts ≦ 20.0 mm)
  • B         2,278   (0.8%) (nodules ≧ 5.1 mm or cysts ≧ 20.1 mm)
  • C                1   (0.0%) (requiring immediate secondary examination)
(Note: Cysts with solid components are treated as nodules).

Number eligible for secondary examination: 2,279
Number of participants in confirmatory (secondary) examination: 2,096
Number with confirmed results : 2,034
Number of fine-needle aspiration cytology (FNAC): 529
Number suspicious or confirmed of malignancy: 112 (including one case of benign nodules)
Number with confirmed tissue diagnosis after surgery: 99
  • 1 benign nodule
  • 95 papillary thyroid cancer
  • 3 poorly differentiated cancer


Full-Scale Screening (April 2014 - March 2016)

Total number targeted: 220,000 in FY2014 (about 385,000 total)
Number of participants in primary examination: 148,027
Number with confirmed results: 121,997

  • A1   50,767 (41.6%) (no nodules or cysts found)
  • A2   70,187 (57.5%) (nodules ≦ 5.0 mm or cysts ≦ 20.0 mm)
  • B       1,043   (0.9%) (nodules ≧ 5.1 mm or cysts ≧ 20.1 mm)
  • C              0   (0.0%) (requiring immediate secondary examination)
(Note: Cysts with solid components are treated as nodules).

Number eligible for secondary examination: 1,043
Number of participants in confirmatory examination: 593
Number with confirmed results: 491
Number of FNAB: 54
Number suspicious or confirmed of malignancy: 15
Number with confirmed tissue diagnosis after surgery: 5
  • 5 papillary thyroid cancer

Unofficial translation of selected tables

Initial Screening

Table 1. Primary examination coverage as of March 31, 2015

Table 2. Number and proportion of children with nodules/cysts as of March 31, 2015

Table 3. Confirmatory examination coverage and results as of March 31, 2015

Cytology results

Table 9. Primary and confirmatory examination results by municipality (Interim report)
Note 10: Excluding duplicates and unconfirmed results.
Note 11: Excluding unconfirmed results. 
Note 12: The number of FNAC, out of (c), including those who were reclassified as A1 or A2.
Note 13: Excluding one suspected case found benign after surgery.
Note 14: Tamura City, Minamisoma City, Date City, Kawamata Town, Hirono Town, Naraha Town, Tomioka Town, Kawauchi Village, Okuma Town, Futaba Town, Namie Town, Katsurao Village and Iitate Village
Note 15: Fukushima City, Koriyama city, Shirakawa City, Sukagawa City, Nihonmatsu City, Motomiya City, Koori Town, Kunimi Town, Otamamura Village, Kagamiishi Town, Tenei Village, Nishigou Village, Izumizaki Village, Nakajima Village, Yabuki Town, Tanagura Town, Yamatsuri Town, Hanawa Town, Samegawa Village, Ishikawa Town, Tamakawa Village, Hirata Village, Asakawa Town, Furudono Town, Miharu Town, and Ono Town
Note 16: Iwaki City, Soma City, Shinchi Town
Note 17: Aizuwakamatsu City, Kitakata City, Shimogo Town, Hinoemata Village, Tadami Town, Minamiaizu Town, Kitashiobara Village, Nishiaizu Town, Bandai Town, Inawashiro Town, Aizubange Town, Yugawa Village, Yanaizu Town, Mishima Town, Showa Village, and Aizumisato Town

Full-Scale Screening

Table 1. Primary examination coverage as of March 31, 2015

Table 2. Number and proportion of children with nodules/cysts as of March 31, 2015

Table 3. Changes in the results of Initial Screening and Full-Scale Screening as of March 31, 2015

Table 4. Confirmatory examination coverage and results as of March 31, 2015

Cytology results

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*Japanese governmental committees run on fiscal year schedules--April to March of the following year--and seem to be required to produce some sort of report, often called an "interim summary," which are essentially the final report. Although it wasn't clearly announced, it seemed to be understood during the March session that the Subcommittee would not meet again and the interim summary would be forwarded to the next session of its parent committee, the Prefectural Oversight Committee for Fukushima Health Management Survey). 

Tuesday, April 28, 2015

Asahi Shimbun GLOBE: The Japanese Government Demanded Revisions of the 2012 WHO Report on Fukushima Radiation Exposure

The December 7, 2014 issue of the Asahi Shimbun GLOBE, a for-fee division of the Asahi Shimbun website, featured a series of articles on World Health Organization (WHO). It included an article whose title translates into "Revision Demanded of the Fukushima Radiation Exposure Report."

A screenshot of the article:
(Not to be copied without permission from Asahi Shimbun).



Below is an unofficial English translation of the article, with the contextually clarified title, posted with permission from the Asahi Shimbun. This post will be no longer available after April 29, 2016 (Japan time).*

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The Japanese Government Demanded Revisions of the 2012 WHO Report on Fukushima Radiation Exposure

Written by Yuri Oiwa

A high level Ministry of Health, Welfare and Labour (MHWL) official heard the cell phone ring. It was a Saturday morning in November 2011. “We have a problem.” It was from a younger colleague who was looking right at a draft copy of the dose estimation report due to the nuclear accident that WHO had been working on.

It showed thyroid exposure doses of 300 to 1000 mSv for infants from Namie Town, Fukushima Prefecture, and 10 to 100 mSv for infants even in Tokyo and Osaka. According to UNSCEAR’s report on Chernobyl, thyroid cancer was found in approximately 6,000 people, and thyroid exposure dose for evacuees was several hundred mSv. Some studies report thyroid cancer increased with exposure dose above 50 mSv.

“WHO’s estimate is substantially higher than the reality.” The Japanese government worked at having WHO revise the estimates by offering new data such as the food monitoring results.

In the WHO dose estimation report released in May 2012, thyroid exposure doses for infants was lowered to 100 to 200 mSv for Namie Town and 1 to 10 mSv for Tokyo and Osaka. As it was felt that this was still dissociated from the reality, the Japanese government requested revisions until moments before the release of the report, with then MHLW Vice Minister Shinji Asonuma conveying disappointment to Margaret Chan.

In February 2013, WHO released a health risk prediction based on these estimates, “In majority of Fukushima residents, a possibility for an obvious increase in cancer is low. Thyroid cancer risk might be increased in some infants.” Lifetime risk for thyroid cancer would be about 1.7 times higher at maximum.

There are 3 full-time employees at WHO in charge of radiation exposure issues. The WHO Fukushima reports were essentially written by an international group of radiation specialists at the request of WHO.

The UNSCEAR report released in April 2014 estimated thyroid exposure dose of 47 to 83 mSv, about half of the WHO estimates, for infants who were in the 20-30 km zone from Fukushima Daiichi NPP. Mikhail Balonov, a professor at the Institute of Radiation Hygiene in Russia and involved with both reports, explained, “UNSCEAR report created after the WHO reports is more realistic, as it reflects evacuation movements of the residents.” As for the criticism that the WHO reports are overestimation, the WHO manager in charge of the reports, Emilie van Deventer, said, “Considering uncertainties of estimation, it is not much different from the UNSCEAR report. The mission of WHO is to protect people’s health. Underestimation of risks must be avoided at any cost.” 



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*Asahi Shimbun charged an annual fee of 12,000 yen plus tax for the secondary use (as in my own translation) of the article in the web. With an 8% sales tax of 960 yen and a domestic bank transfer fee of 324 yen, the total came to 13,284 yen (or $111.75 at today's exchange rate). According to the rules set by the Asahi Shimbun, excerpting did not require permission, but it necessitated a longer article to insert only parts of the translation. In order to avoid selection bias, a decision was made to personally pay the fee for one year so the information can be shared in its entirety, free of any personal biases. 

Copying the translation for reposting is permitted only if the entire translation is copied so as not to create any misunderstanding. This does not include the screenshot of the original article shown above, which requires permission from Asahi Shimbun.


Friday, February 13, 2015

Fukushima Thyroid Examination, February 2015: 117 Potential Thyroid Cancer Cases, 87 Confirmed and 30 Awaiting Surgery--109 from 1st Round and 8 from 2nd Round Screening

The Eighteenth Prefectural Oversight Committee for Fukushima Health Management Survey convened in Fukushima City, Fukushima Prefecture, on February 12, 2015, releasing the latest results of thyroid examination, consisting of Initial Screening or the first-round screening (originally scheduled to be conducted from October 2011 to March 2014, but actually still ongoing) and Full-Scale Screening or the second-round screening (beginning April 2014).

An official English translation of the results is now available here.

It has only been 7 weeks since the normally quarterly Oversight Committee last met on December 25, 2014. The latest results include two more months worth of results confirmed as of December 31, 2014. 


In a nutshell, there are now 3 more (2 from the first-round and 1 from the second-round) confirmed cancer cases, all papillary thyroid cancer, and 5 more (1 from the first-round and 4 from the second-round) newly suspicious cases.

Initial Screening (the first-round) targeted about 368,000 individuals who were age 18 and younger, residing in Fukushima Prefecture at the time of the Tokyo Electric Fukushima Daiichi nuclear power plant accident on March 11, 2011. 

Full-Scale Screening (the second-round), to be conducted every 2 years until age 20 and every 5 years after age 20, additionally targets those who were born in the first year after the accident, aiming to examine approximately 385,000 individuals in a 2-year period. 

Curiously, officials are still accepting first-time subjects in the first-round screening in an attempt to raise the participation rate, allowing those who haven't yet undergone Initial Screening to participate in it so as long as they have not received a notice for Full-Scale Screening. As a result, 81.2% of those eligible have now undergone the primary ultrasound examination, either in Fukushima Prefecture or in other prefectures where they have relocated to. This is 0.5% more than the results released on December 25, 2014. 

As a whole, of 367,687 eligible, 298,577 (81.2%) underwent the first-round screening and 297,046 (99.5%) had confirmed results: 153,017 (51.5%) with A1 (no ultrasound findings) test results, 141,778 (47.7%) with A2 (to be followed with observation; see the summary results below for criteria for A2 and B), and 2,250 (0.8%) with B (eligible for secondary examination). Of 1,991 more who underwent the first-round in November and December, 793 had confirmed results as of December 31, 2014: 384 with A1, 399 with A2, and 10 with B. All 10 individuals with B were from the FY 2013 targeted municipalities. 16 more underwent the secondary examination from the first-round with 15 confirmed results including 4 cases that had fine-needle aspiration cytology (FNAC) , and one person, a female from Iwaki City who was age 17 at the time of the accident, was found to be suspected of cancer. Additionally, 2 more were confirmed of papillary thyroid cancer after surgery. As usual, no details were given in regards to age/sex/TNM classification of surgical cases.

The second-round has so far covered nearly half of about 220,000 residents from 25 municipalities targeted for examination in Fiscal Year 2014, ending on March 31, 2015. 75,311 had confirmed results as of December 31, 2014: 31,789 (42.2%)  with A1 test results, 42,911 (57.0%) with A2, and 611 (0.8%) with B. As of December 31, 2014,168 were newly categorized as B, 129 more underwent secondary examination, 107 more had confirmed results and 11 more underwent fine-needle aspiration cytology and 4 were found to be suspicious of malignancy: 1 male (age 13 at the time of the accident) and 3 females (age 10, 13 and 13 at the time of the accident). Their first-round test results were either A1 (2 cases) or A2 (2 cases) . The four are from three FY 2011 municipalities--Namie Town, Date City and Tamura City, and Fukushima City which was a FY 2012 municipality. So far a total of 8 cases, including the newly diagnosed 4, are found to be suspicious of malignancy from the second-round. One suspect case announced in the last Committee meeting has been confirmed of papillary thyroid cancer after post-surgical tissue diagnosis.

The second-round appears to have a higher percentage of A2 at 57.0% than the first-round at 47.7%, but nearly all of them appear to be cysts. The second-round also has a lower percentage of A1 at 42.2%, as opposed to the first-round at 51.5%. These trends appear to be seen across all age groups. On the other hand, the proportion of B is fairly consistent across the board at 0.8% .

The proportion of those who underwent FNAC has significantly decreased in each successive year: 64.5% in FY 2011, 43.7% in FY 2012, 28.9% in FY 2013, and 13.1% in FY 2014. Shinichi Suzuki, a Fukushima Medical University professor and the head of thyroid examination program, explained that the FNAC rate was high in FY 2011 as they were being overcautious. He assured that the diagnostic guidelines were established to avoid overdiagnosis, and those guidelines remained the same since thyroid examination was launched, but some of the first cases asked for FNAC just to be certain there was no cancer and they were not turned down. In the second-round, there are simply fewer cases that meet criteria for FNAC.

There was a leak of information the day before the Committee met, pertaining to the confirmed cancer case from the second-round. Committee chair and vice-chair boh expressed their displeasure and disappointment, asking the media to be respectful so that information won't be misunderstood. They also stated that knowing an insider leaked information created an uncomfortable work environment. They repeatedly asked the media to wait until after the Committee presented the information in context. A member of the media who published leaked news articles in the past claimed freedom for the press to publish as it wishes.

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A summary of results are provided for Initial Screening and Full-Scale Screening.

Initial Screening (October 2011 - ongoing)

Total number targeted: 367,687
Number of participants in primary examination as of December 31, 2014: 298,577
Number with confirmed results as of December 31, 2014: 297,046

  • A1   153,017 (51.5%) (no nodules or cysts found)
  • A2   141,778 (47.7%) (nodules ≦ 5.0 mm or cysts ≦ 20.0 mm)
  • B         2,250   (0.8%) (nodules ≧ 5.1 mm or cysts ≧ 20.1 mm)
  • C                1   (0.0%) (requiring immediate secondary examination)
(Note: Cysts with solid components are treated as nodules).

Number eligible for secondary examination: 2,251
Number of participants in secondary examination as of December 31, 2014: 2,067
Number with confirmed results as of December 31, 2014: 2,010
Number of fine-needle aspiration cytology (FNAC) as of December 31, 2014: 523
Number suspicious or confirmed of malignancy: 110 (often referred to as 109, excluding the case of benign nodule)
Number with confirmed tissue diagnosis after surgery as of December 31, 2014: 87
  • 1 benign nodule
  • 83 papillary thyroid cancer
  • 3 poorly differentiated cancer

Full-Scale Screening (April 2014 - March 2016)

Total number targeted: 220,000 in FY2014 (about 385,000 total)
Number of participants in primary examination as of December 31, 2014: 106,068
Number with confirmed results as of December 31, 2014: 75,311

  • A1   31,789 (42.2%) (no nodules or cysts found)
  • A2   42,911 (57.0%) (nodules ≦ 5.0 mm or cysts ≦ 20.0 mm)
  • B          611   (0.8%) (nodules ≧ 5.1 mm or cysts ≧ 20.1 mm)
  • C              0   (0.0%) (requiring immediate secondary examination)
(Note: Cysts with solid components are treated as nodules).

Number eligible for secondary examination: 611
Number of participants in secondary examination as of December 31, 2014: 377
Number with confirmed results as of December 31, 2014: 262
Number of FNAB as of December 31, 2014: 22
Number suspicious or confirmed of malignancy: 8
Number with confirmed tissue diagnosis after surgery as of December31, 2014: 1


Overall, the number of suspicious or confirmed of malignancy is 118, including a case of post-surgically diagnosed benign nodule. (This number might be referred to as 117, excluding the benign nodule case). Of these, 87 are surgically confirmed as thyroid cancer (84 papillary thyroid cancer and 3 poorly differentiated cancer) and 30 are suspicious of malignancy awaiting surgery, including 1 new case from the first-round and 4 new cases from the second-round.

In regards to detailed characteristics of some of the malignant cases, such as metastases, staging, surgical methods, and genetic analysis, refer to this post describing information gathered from various sources. (Such information is not readily provided, as biopsy as well as surgical cases are technically no longer part of the screening and personal data is guarded, almost over-rigorously). Suzuki declined to reveal the proportion of cases with lymph node metastasis during the press conference, citing privacy concern due to surgery being part of regular medical care. Nevertheless, he did say that it was about the same as previously released at the November 11, 2014 Thyroid Examination Evaluation Subcommittee, which was 74%.

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Below are translations of some of the tables in the results.

Initial Screening

Table 1. Primary examination results as of December 31, 2014

Table 2. Number and proportion of participants with nodules/cysts as of December 31, 2014

Table 3. Secondary examination: progress and results as of December 31, 2014

Table 4. Results of FNAC

Table 9: Regional comparison of suspicious/malignant cases
Note 10: Excluding duplicate data and unconfirmed results.
Note 11: Excluding unconfirmed results. 
Note 12: The number of FNAC, out of (c), including those who were reclassified as A1 or A2.
Note 13: Excluding one case that was suspected of malignancy but turned out to be benign after surgery.
Note 14: Tamura City, Minamisoma City, Date City, Kawamata Town, Hirono Town, Naraha Town, Tomioka Town, Kawauchi Village, Okuma Town, Futaba Town, Namie Town, Katsurao Village and Iitate Village
Note 15: Fukushima City, Koriyama city, Shirakawa City, Sukagawa City, Nihonmatsu City, Motomiya City, Koori Town, Kunimi Town, Otamamura Village, Kagamiishi Town, Tenei Village, Nishigou Village, Izumizaki Village, Nakajima Village, Yabuki Town, Tanagura Town, Yamatsuri Town, Hanawa Town, Samegawa Village, Ishikawa Town, Tamakawa Village, Hirata Village, Asakawa Town, Furudono Town, Miharu Town, and Ono Town
Note 16: Iwaki City, Soma City, Shinchi Town
Note 17: Aizuwakamatsu City, Kitakata City, Shimogo Town, Hinoemata Village, Tadami Town, Minamiaizu Town, Kitashiobara Village, Nishiaizu Town, Bandai Town, Inawashiro Town, Aizubange Town, Yugawa Village, Yanaizu Town, Mishima Town, Showa Village, and Aizumisato Town

〈Discussion of regional comparison results〉
  • Analysis of 297,046 primary examination participants, excluding duplicates and unconfirmed results, by regions revealed that proportions of B&C tended to increase in the order of "13 municipalities including the evacuation zone," "Nakadori," "Hamadori," and "Aizu region."
  • On the other hand, proportions of suspicious or malignant cases was about the same in "13 municipalities including the evacuation zone," "Nakadori," and "Hamadori," but a little lower in "Aizu region." This is probably because the proportion of those who completed the secondary examination is lower in Aizu region compared to the other areas. 
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Full-Scale Screening

Table 1. Primary examination progress as of December 31, 2014

Table 2. Number and proportion of participants with nodules/cysts as of December 31, 2014

Table 3. Transition from Initial Screening to Full-Scale Screening

Note 1: The upper row shows the number whose Full-Scale Screening results were confirmed, and the lower row the proportion (%).
Note 2: The upper row shows the Initial Screening result in the corresponding diagnostic category in Full-Scale Screening, and the lower row the proportion (%).


Of 74,700 who were classified as A1 (31,789) or A2 (42,911)  in Full-Scale Screening, 69,948 were also classified as A1 or A2 in Initial Screening. Also, of 611 who were classified as B, 441 were A1 or A2 in Initial Screening.

(Also notable is the fact there are 4,661 that did not go through Initial Screening. 16 had test result B in Full-Scale Screening. As explained above, officials are still allowing some to undergo Initial Screening, but it creates sort of a double standard to include some of those never examined in Initial Screening and some in Full-Scale Screening).

Table 4. Secondary examination progress and results as of December 31, 2014

Table 5. Results of FNAC


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Thursday, December 25, 2014

Fukushima Thyroid Examination: 112 Children Suspected (28 Cases) or Confirmed (84 Cases) with Thyroid Cancer--108 from Initial Screening and 4 from Full-Scale Screening

The Seventeenth Prefectural Oversight Committee convened in Fukushima City, Fukushima Prefecture, on December 25, 2014, releasing the latest results of thyroid examination, consisting of Initial Screening or the first-round (originally scheduled to be conducted from October 2011 to March 2014, but actually still ongoing) and Full-Scale Screening or the second-round (beginning April 2014).

An official English translation of the results is available here.

Initial Screening targeted about 368,000 individuals who were age 18 and younger, residing in Fukushima Prefecture at the time of the Tokyo Electric Fukushima Daiichi nuclear power plant accident on March 11, 2011. About 80% of those eligible have undergone the primary ultrasound examination, either in Fukushima Prefecture or in other prefectures where they have relocated to. Full-Scale Screening, to be conducted every 2 years until age 20 and every 5 years after age 20, additionally targets those who were born in the first year after the accident, aiming to examine approximately 385,000 individuals in a 2-year period. 

Notably, there was a leak of information the day before the committee met, pertaining to four cases from Full-Scale Screening discovered to be suspicious of malignancy, as described in this post. These four cases caused quite a shock as Initial Screening, considered to provide a baseline incidence rate from the prevalence rate obtained as a result of the wide-scale screening, supposedly would have detected all the cases with "pre-existing" tumors. These "pre-existing" or "latent" cancers would have been discovered before becoming symptomatic due to screening. (It is important to note that Shinichi Suzuki, a Fukushima Medical University thyroid surgeon in charge of the thyroid examination, has steadfastly declined to provide the number of children--some are now adults, over 3 years after the accident--who might have had subjective symptoms). In other words, the incidence rate from the second-round of screening would be expected to be lower.

The four cases, 3 males (ages 6, 10, and 17 at the time of the accident) and 1 female (age 15 at the time of the accident), were either A1 (2 cases) or A2 (2 cases) in Initial Screening. Suzuki was grilled about whether these might have been missed diagnoses in Initial Screening, both during the committee meeting and the press conference, and he flatly denied such possibilities stating the retrospective review of the ultrasound images did not reveal any missed lesions. This, however, means the tumors newly arose since Initial Screening in at least 2 of the cases previously classified as A1, which by definition had no nodules or cysts. Suzuki refused to provide the tumor diameter and the speed of tumor growth for each of the four individuals, citing that they were no longer considered part of the screening and thus patient privacy overruled any other obligation for information release. 

The male to female ratio of 3:1 is also unexpectedly high, as thyroid cancers are usually more common in females, except as discovered after the Chernobyl accident. However, Suzuki stated that nothing conclusive can be drawn from merely 4 cases, and they would have to keep an eye on the future development. Eventually Suzuki used these 4 cases to emphasized the importance of participating in Full-Scale Screening even though the Initial Screening result was normal, as in A1. 

If Suzuki was at all puzzled by the contradiction presented by the situation, he did not show it. An unexpectedly high prevalence rate of thyroid nodules and cancer detected in Initial Screening has been attributed to the highly sensitive ultrasound equipment picking up very small tumors. Today Suzuki emphasized the limitation of ultrasound as it might not always detect what's there. Also, Suzuki has repeatedly mentioned how slowly thyroid cancers grow. Then why did these 4 cases become detectable in two and a half years or less? It seems as if he is hiding behind "patient privacy" so as not to reveal some inconvenient truths. 

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A summary of results are provided for Initial Screening and Full-Scale Screening.

Initial Screening (October 2011 - ongoing)

Total number targeted: 367,686
Number of participants in primary examination as of October 31, 2014: 296,586
Number with confirmed results as of October 31, 2014: 296, 253

  • A1   152,633 (51.5%) (no nodules or cysts found)
  • A2   141,379 (47.7%) (nodules ≦ 5.0 mm or cysts ≦ 20.0 mm)
  • B         2,240   (0.8%) (nodules ≧ 5.1 mm or cysts ≧ 20.1 mm)
  • C                1   (0.0%) (requiring immediate secondary examination)
(Note: Cysts with solid components are treated as nodules).

Number eligible for secondary examination: 2,241
Number of participants in secondary examination as of October 31, 2014: 2,051
Number with confirmed results as of October 31, 2014: 1,985
Number of fine-needle aspiration biopsy (FNAB) as of October 31, 2014: 519
Number suspicious or confirmed of malignancy: 109 (often referred to as 108, excluding the case of benign nodule)
Number undergoing surgery as of October 31, 2014: 85
  • 1 benign nodule
  • 81 papillary thyroid cancer
  • 3 poorly differentiated cancer

Full-Scale Screening (April 2014 - March 2016)

Total number targeted: 220,000 in FY2014 (about 385,000 total)
Number of participants in primary examination as of October 31, 2014: 82,101
Number with confirmed results as of October 31, 2014: 60,505

  • A1   25,563 (42.2%) (no nodules or cysts found)
  • A2   34,485 (57.0%) (nodules ≦ 5.0 mm or cysts ≦ 20.0 mm)
  • B          457   (0.8%) (nodules ≧ 5.1 mm or cysts ≧ 20.1 mm)
  • C              0   (0.0%) (requiring immediate secondary examination)
(Note: Cysts with solid components are treated as nodules).

Number eligible for secondary examination: 457
Number of participants in secondary examination as of October 31, 2014: 248
Number with confirmed results as of October 31, 2014: 155
Number of FNAB as of October 31, 2014: 11
Number suspicious or confirmed of malignancy: 4
Number undergoing surgery as of October 31, 2014: 0


Overall, the number of suspicious or confirmed of malignancy is 113, including a case of post-surgically diagnosed benign nodule. (This number might be referred to as 112, excluding the benign nodule case). Of these, 84 are surgically confirmed as thyroid cancer (81 papillary thyroid cancer and 3 poorly differentiated cancer) and 29 are suspicious of malignancy awaiting surgery, including 5 new cases from Initial Screening and 4 from Full-Scale Screening.

In regards to detailed characteristics of some of the malignant cases, such as metastases, staging, surgical methods, and genetic analysis, refer to this post describing information gathered from various sources. (Such information is not readily provided, as biopsy as well as surgical cases are technically no longer part of the screening and personal data is guarded, almost over-rigorously). 

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Below are translations of some of the tables in the results.

Initial Screening

Table 1. Primary examination results as of October 31, 2014

Table 2. Number and proportion of participants with nodules/cysts as of October 31, 2014

Table 3. Secondary examination: progress and results as of October 31, 2014

Table 4. Results of FNAB

Table 9: Regional comparison of suspicious/malignant cases


Note 10: Excluding duplicate data and unconfirmed results.
Note 11: Excluding unconfirmed results. 
Note 12: The number of FNAB, out of (c), including those who were reclassified as A1 or A2.
Note 13: Excluding one case that was suspected of malignancy but turned out to be benign after surgery.
Note 14: Tamura City, Minamisoma City, Date City, Kawamata Town, Hirono Town, Naraha Town, Tomioka Town, Kawauchi Village, Okuma Town, Futaba Town, Namie Town, Katsurao Village and Iitate Village
Note 15: Fukushima City, Koriyama city, Shirakawa City, Sukagawa City, Nihonmatsu City, Motomiya City, Koori Town, Kunimi Town, Otamamura Village, Kagamiishi Town, Tenei Village, Nishigou Village, Izumizaki Village, Nakajima Village, Yabuki Town, Tanagura Town, Yamatsuri Town, Hanawa Town, Samegawa Village, Ishikawa Town, Tamakawa Village, Hirata Village, Asakawa Town, Furudono Town, Miharu Town, and Ono Town
Note 16: Iwaki City, Soma City, Shinchi Town
Note 17: Aizuwakamatsu City, Kitakata City, Shimogo Town, Hinoemata Village, Tadami Town, Minamiaizu Town, Kitashiobara Village, Nishiaizu Town, Bandai Town, Inawashiro Town, Aizubange Town, Yugawa Village, Yanaizu Town, Mishima Town, Showa Village, and Aizumisato Town

〈Discussion of regional comparison results〉
  • Analysis of 296,253 primary examination participants, excluding duplicates and unconfirmed results, by regions revealed that proportions of B&C tended to increase in the order of "13 municipalities including the evacuation zone," "Nakadori," "Hamadori," and "Aizu region."
  • On the other hand, proportions of suspicious or malignant cases was about the same in "13 municipalities including the evacuation zone," "Nakadori," and "Hamadori," but a little lower in "Aizu region." This is probably because the proportion of those who completed the secondary examination is lower in Aizu region compared to the other areas. 
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Full-Scale Screening

Table 1. Primary examination progress as of October 31, 2014

Table 2. Number and proportion of participants with nodules/cysts as of October 31, 2014

Table 3. Transition from Initial Screening to Full-Scale Screening

Note 1: The upper row shows the number whose Full-Scale Screening results were confirmed, and the lower row the proportion (%).
Note 2: The upper row shows the Initial Screening result in the corresponding diagnostic category in Full-Scale Screening, and the lower row the proportion (%).


Of 60,048 who were classified as A1 (25,563) or A2 (34,485) categories in Full-Scale Screening, 56,204 were also classified as A1 or A2 in Initial Screening. Also, of 457 who were classified as diagnostic category B, 333 were A1 or A2 in Initial Screening.

Also notable is the fact that, of the 3,776 previously unexamined individuals who participated in Full-Scale Screening, 16 were classified in the diagnostic category of B.

Table 4. Secondary examination progress and results as of October 31, 2014

Table 5. Results of FNAB

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