Fukushima Thyroid Examination September 2022: 236 Surgically Confirmed as Thyroid Cancer Among 284 Cytology Suspected Cases

  

Overview

     On September 1, 2022, the 45th session of the Oversight Committee for the Fukushima Health Management Survey (FHMS) convened online and in Fukushima City, releasing a new set of results (data up to March 31, 2022) from the fourth and fifth rounds as well as the Age 25 Milestone Screening of the Thyroid Ultrasound Examination (TUE).  Four and a half months have elapsed since the previous session held on May 13, 2022 (see previous post). This time 6 months worth of data was released, narrowing the widened gap between compilation and report dates of the data. (Only 3 months worth of data was reported at the last session despite the 7-month pause since the previous session. ) Still it's not the most recent data possible because FMU could have reported data through June. 

     As the data is usually compiled every 3 months, data between October 1, 2021 and December 31, 2021 was released separately as supplementary materials for both the fourth and fifth rounds in addition to data between October 1, 2021 and March 31, 2022. The Age 25 Milestone Screening data report, biannually released, is right on schedule. The fifth-round data reported this time includes the age and sex distribution of cancer cases for the first time. Also a brief update was reported on the second-round data with an addition of one surgical case.

     The 45th session now consists of a full roster of 18 members with Nobuyuki Hirohashi of Hiroshima University replacing former Vice Chair Toshiya Inaba who abruptly resigned at the last session. Chair Noboru Takamura, a disciple of Shunichi Yamashita, has to be given credit for presiding over the meetings in a calm and logical manner despite his history of downplaying radiation health effects (see the previous post). This peaceful proceeding is in contrast to how dramatic and emotional it had been under the previous Chair Hokuto Hoshi who is now an LDP Upper House member representing Fukushima Prefecture. However, the moderator who is deputy chief of the Section of FHMS in the prefectural government has a strict and stern attitude during the press conference, severely and often rudely limiting question topics and time.

     Official English translation (link) has been added for two more sessions and now is available up to the 42nd session (PDF link) of the Oversight Committee on this page of the website of the Radiation Medical Science Center of the Fukushima Health Management Survey (RMSC/FHMS). This website also shows an outline of the FHMS and TUE itself.

   
Highlights
  • The second round: 1 new surgical case.
  • The fourth round: 2 new cases diagnosed as suspicious or malignant, and 2 new surgical cases. 
  • The fifth round: 5 new cases diagnosed as suspicious or malignant, and 3 new surgical cases.
  • Age 25 Milestone Screening: 3 new cases diagnosed as suspicious or malignant, and 4  new surgical cases.
  • Total number of suspected/confirmed thyroid cancer has increased by 10 to 284116 in the first round (including a single case of benign tumor), 71 in the second round, 31 in the third round, 39 in the fourth round, 11 in the fifth round, and 16 in Age 25 Milestone Screening.
  • Total number of surgically confirmed thyroid cancer cases has also increased by 10 to 236 (101 in the first round, 56 in the second round, 29 in the third round, 34 in the fourth round, 6 in the fifth round, and 10 in Age 25 Milestone Screening,

The latest overall results including the "unreported" and cancer registry cases
     Please refer to the the post on May 2021 report regarding the details of "unreported" cases and cancer registry data. (A July 2018 post describes the origin of the first 11"unreported" cases, and their histological diagnoses were obtained from this paper.)

     The official count, as reported above and also in the summary document shown in the next section, is 284 suspected/confirmed and 236 surgically confirmed thyroid cancer cases. With an addition of the most recent numbers for both "unreported" cases (see this post) and "outside" cases discovered in the cancer registry (updated at the 19th session of the TUE Subcommittee), the count increases to 362 cytologically suspected/confirmed and 297 surgically confirmed cancer cases. 
     It should be noted that the actual number of cases is likely more due to lack of any past, present or future exhaustive investigation by Fukushima Medical University (FMU), which is necessary to gather all the cancer cases discovered outside the framework of the FHMS-TUE.


Summary on the current status of the TUE
    A seven-page summary of the first through fifth rounds as well as the Age 25 Milestone Screening, "The Status of the Thyroid Ultrasound Examination Results," lists key findings from the primary and confirmatory examinations as well as the surgical information. 
    Below is an unofficial translation of this summary which is not officially translated.


The first round
     There is no change in data with 116 suspected/confirmed thyroid cancer cases (39 males and 77 females), of which 102 underwent surgery confirming 1 benign nodule and 101 thyroid cancer cases (100 papillary thyroid cancer and 1 poorly-differentiated cancer). 
     The last update as of FY 2015 was reported at the 23rd session in June 2016 (Japanese, English).

The second round
   There is no change in the number of suspected/confirmed thyroid cancer cases at 71 (32 males and 39 females). There was one new surgical case in the second round which was diagnosed as papillary thyroid cancer, increasing the confirmed cancer cases to 56 (55 papillary thyroid cancer and 1 "other" thyroid cancer) as shown in the brief update
     The most recent FY2020 update of the second round data was previously reported at the 42nd session (Japanese, English).

The third round
     There is no change in data with 31 suspected/confirmed thyroid cancer cases (13 males and 18 males), of which 29 were surgically confirmed as papillary thyroid cancer. The final report from the 39th session in August 2020 (JapaneseEnglishwas updated as of FY2020 and reported at the 42nd session in July 2021 (Japanese, English).
      FMU is currently conducting an analysis of the third-round data, which has been presented to the TUE Subcommittee. FMU does not allow outside researchers to handle the data, yet FMU researchers conducting the analysis seem to lack expertise in statistical analysis which was apparent in the analysis of the second-round data (see this post). Recent TUE Subcommittee sessions have all but morphed into an "open statistical lecture series" with two subcommittee members, Tomotaka Sobue of Osaka University and Kota Katanoda of the National Cancer Center, giving advices and feedbacks on the analytical results presented by FMU. 
     At the 45th session of the Oversight Committee, a summary of the most recent TUE Subcommittee session--the 19th session held on August 1, 2022--was reported. The summary includes the interim results of the nested case control study which show an increased odds ratio at higher doses in any matching models (see pages 21, 25, 29, 33, 37, and so on, of the session summary) (added on September 19, 2022), but FMU claims the number of cases is too small and there is no statistical significance. Because only about half of the thyroid cancer cases have reconstructed doses, it was suggested that the third- and fourth-round data be analyzed together in order to increase the statistical power. This suggestion was approved by the Oversight Committee, and the joint analysis will begin when the final report of the fourth round becomes available. Although this might seem like a feasible idea, it does blur the line between the rounds.

The fourth round
    The fourth round, originally scheduled from April 1, 2018 through March 31, 2020, is winding down. Only 24 more participated in the primary examination between October 1, 2021 and March 31, 2022, with no change in participation rate of 
62.3%. This is still below what the prior rounds registered (81.7% for the first round, 71.0% for the second round, and 64.7% for the third round).
     No one newly received the "B" assessment. Five newly participated in the confirmatory examination with 2 undergoing FNAC (fine-needle aspiration cytology). They, two females, were both diagnosed with suspected thyroid cancer. One, diagnosed between October and December 2021, was age 9 at the time of the 2011 nuclear accident. She is from a FY2018- targeted municipality and resided in Aizu. Her third-round result was A2 nodules. The other one, diagnosed between January and March 2022,  was age 14 and resided in Nakadori in 2011. She was never examined prior to the fourth round. 
   Two (one each from FY 2018 and FY2019 municipalities) were newly confirmed with papillary thyroid cancer after undergoing surgery. 

    In summary, as of September 30, 2021, the number of suspected or confirmed thyroid cancer cases for the fourth round is 39, of which 34 have been surgically confirmed as papillary thyroid cancer. 
    The previous results from the third round are as follows: 26 with "A" (6 with A1, 13 with A2 cysts, 6 with A2 nodules, and 1 with A2 cysts and nodules), 9 with "B," and 4 with no prior result. 

The fifth round
    The fifth round targets 252,902 individuals, excluding about 21,000 born in FY 1996 (April 2, 1996 to April 1, 1997) and about 20,000 born in FY 1997 (April 2, 1997 to April 1, 1998) who are earmarked for the Age 25 Milestone Examination in FY 2021-2022. (It has previously been discussed how this exclusion skews age distribution graphs to the left.)
    The COVID-19 restrictions have had a significant impact on the progress of the fifth round which began in April 2020: school closures initially halted the school-based screening, and a burden on medical facilities reduced participation in the confirmatory examination. [Note: The fifth round was originally earmarked for FY 2020-2021 (April 2, 2020 to March 31, 2022), but the pandemic has forced an extension of the screening period by one year as described in this proposal: Elementary and middle school students from FY 2020 municipalities will undergo the TUE in FY 2020-2021, while FY 2021 municipalities will be pushed to FY 2022. For high school students, the TUE will be conducted in FY 2021-2022 with the exception of those who were already examined in FY 2020.] 
     The sixth round is expected to return to a two-year screening cycle beginning April 2023.

     As of March 31, 2022, 74,986 participated in the primary examination, including 29,104 new participants, and its participation rate increased from 18.1% to 29.6%, still quite low. Participation rates by age group increased from 31.3% to 48.1% in ages 8-11, from 20.1% to 36.0% in ages 12-17, and from 7.4% to 10.3% in ages over 18. The primary examination results available nearly doubled to 69,822 (93.1%), and so did the number of "B" assessment to 869 (an additional 411 new cases) which qualifies for the confirmatory examination. 
     Two hundred seventy-nine newly participated in the confirmatory examination, 15 underwent FNAC, and 5 (all females) were diagnosed with suspected thyroid cancer. One was diagnosed from 5 FNAC participants between October and December 2021, and she is from a FY2021 municipality. Her previous result was A1. Remaining 4 were diagnosed from 10 FNAC participants, and 3 are from FY2020 municipalities and 1 from a FY2021 municipality. Their previous results include 1 with A1 and 3 with A2 cyst. 
     Age and sex distributions of suspected/confirmed cancer cases for the fifth round are available for the first time, likely because the number of suspected/confirmed cancer cases reached two digits. It shows 3 were ages 5 or younger at the time of the March 2011 nuclear accident: a male at age 2, a female at age 4, and a female at age 5.
     Two from FY 2020 municipalities and 1 from a FY2021 municipality have been confirmed with papillary thyroid cancer after undergoing surgery.

   In summary, as of March 31, 2022, the number of suspected or confirmed thyroid cancer cases for the fifth round is 11, of which 6 have been surgically confirmed as papillary thyroid cancer. 
   The previous results from the fourth round are as follows: 8 with "A" (3 with A1, 4 with A2 cysts, 1 with A2 nodules), 2 with "B," and 1 with no prior result. 

Age 25 Milestone Screening
    In the Age 25 Milestone Screening, each screening year targets a cohort turning 25 during each fiscal year, and the results are reported every 6 months. The most recent implementation schedule available in English is from September 2020, which was reported to the 41st session of the Oversight Committee and can be found here(No one is supposed to undergo a regular TUE within 2 years of becoming eligible for the Age 25 Milestone Screening.) Although each fiscal-year screening is earmarked for those turning 25 during that fiscal year, participants can take part in the screening anytime up to the year before they become eligible for the Age 30 Milestone Screening. 
    
Note: Transition of each FY birth cohort to the Age 25 Milestone Screening reduces a target population for the main TUE. This reduction began in the third round conducted during FY 2016-2017, which excluded the FY 1992 and 1993 cohorts in anticipation of the upcoming Age 25 Milestone Screening. With each FY birth cohort including about 22,000 individuals, this is a sizable reduction which continues as the TUE target population ages. An exception is an increase from 367,637 for the first round to 381,237 for the second round which is due to an inclusion of those who were in utero at the time of the accident). From then on, it has decreased to 336,667 for the third round, 294,228 for the fourth round, and now 252,902 for the fifth round.

    The results reported this time are from the data up to March 31, 2022, and this time some regional data (only for the primary examination) is reported, following the first-time appearance of age and sex distribution graphs for suspected and confirmed cancer cases in the last report. FY1996 cohort began screening this fiscal year (FY2022), and their primary examination results are included this time, but this data is excluded from the secondary examination results at this time due to a limited number of participants. Moreover in FY2022, those born in FY1992 became eligible to participate in the Age 30 Milestone Screening, but no data was reported on this.
     Since the previously reported results as of September 30, 2021, target population increased to 108,713 due to an addition of 21,020 born in FY2016. The primary examination participation increased by 1,678 to total participants of 9,841, but the participation rate actually decreased slightly from 9.3% to 9.1% due to a larger denominator from the target population increase.
    An additional 90 participants received "B" assessment in the primary examination, and a total of 504 qualified for the confirmatory examination. Seventy-four of 90 participants with newly assessed "B" are from FY1996 who were excluded from the report this time. Thus the confirmatory examination results covered 430 who are eligible, an increase of 16 since the last report. Twenty-five more participated in the confirmatory examination, making the total participants 353, and 345 (39 more than last time) have the final results. After FNAC was conducted in 6 individuals (with total FNAC cases of 31), 3 individuals (all females who were age 15 at exposure) were diagnosed with suspected thyroid cancer. Their prior screening results were 2 with A2 cysts and 1 with no prior screening. Regional data reported for the first time only includes the primary examination data, and no information is available as to residence location information of these cases.

     In summary, the number of suspected or confirmed thyroid cancer cases from the Age 25 Milestone Screening increased by 3 to 16. The results from the prior screening are: 4 with "A" (1 with A2 nodules, 3 with A2 cysts), 3 with "B" and 9 with no prior screening.
     Four new surgical cases (all papillary thyroid cancer) were added, and the number of surgically confirmed thyroid cancer increased to 10, including 9 papillary thyroid cancers and 1 follicular thyroid cancer.

     Note: The FNAC results this time show a minimum tumor diameter of 5.3 mm, which is 0.9 mm smaller than last reported. This means that newly detected tumors are smaller and thus potential candidates for non-surgical active surveillance. Of 16 suspected thyroid cancer cases, 10 have undergone surgery. With the cancer cases being mostly in their late 20's, there is a possibility that remaining 6 are under active surveillance. 

Sex ratio

     All 10 newly diagnosed with suspected thyroid cancer are females this time. A female to male ratio has increased significantly to 10:1 in the fifth round, and there is a mild increase to 3:1 in the Age 25 Milestone Screening. FMU suggested 3 possible explanations for this increase: 

1) Nodules tend to be detected more in females; 

2) Progress status of the fifth round up to March 2022 does not include the results of the school-based screening with younger participants in Hamadori and Aizu, which just started in April 2022; and 

3) There are more females than males participating in the Age 25 Milestone Screening. The primary examination results by sex in Appendix 4 of the most recent report show nearly twice as many female participants than males (6,233 vs. 3,287). This tendency was already seen in data up to September 2020 (3,884 females vs. 2,023 males) in the latest available English translation of the report from the 41st session. 

     However, the fifth-round sex ratio is likely to change since it is still progressing.

Expected upcoming changes in the dataset
     
     There are two factors inherent to the implementation structure of the TUE, leading to a smaller dataset with each screening cycle. One is a reduced size of target population and the other is a decline in participation rates, both of which are already being observed and expected to progress.
     As described above, a shift of a cohort to the Milestone Screening (Age 25, Age 30, etc.) with time reduces the target population in each successive screening cycle. Furthermore, school-based screening conducted through high school slows down with each cohort graduating from high school. It will eventually come to a natural halt when the youngest cohort born in FY2011 (between April 2, 2011 and April 1, 2012) finishes high school in 2029. It should be noted that the school-based screening is completely voluntary, no less the TUE itself.
     Convenience of the school-based screening contributes to a higher participation rate for ages up to 18 than past age 18. This is clearly shown in the most recent participation rates by age reported in this post: 48.1% in ages 8-11, 36.0% in ages 12-17, and 10.3% in ages over 18 in the fifth round, and 9.1% for the Age 25 Milestone Screening. 
     It is critical to recognize these expected changes for future datasets when reviewing the TUE data because they cast doubt on reliability and integrity of the TUE data itself and any analysis conducted. Retrieval of "missing data" due to "unreported cases" at any age is being attempted by matching the TUE data with regional (up to 2015) and national (from 2016 on) cancer registry data. For instance, reconciliation with the most recently available national cancer registry data up to 2018  (document from the 19th Subcommittee session) revealed 43 cases from the cancer registry, which are not included in the official TUE count. This is an increase from 27 cases up to 2017 (reported to the 18th Subcommittee session). Nonetheless the cancer registry is far from fool-proof because patients who move their official residence registry outside Fukushima are not reported as Fukushima cases.

UNSCEAR2020/2021 Report

     UNSCEAR Report 2020/2021 (press release) concluded that future health effects, e.g. cancer directly related to radiation exposure from the 2011 Fukushima Daiichi Nuclear Accident are not likely to be discernible. Main findings of UNSCEAR 2020/2021 were introduced to the Oversight Committee 3 times this year: the 44th session in May, the 19th Subcommittee session in August, and at the 45th session in September during a report on proceedings of the 19th Subcommittee session. 
     This redundancy is telling and believed to reflect an ulterior motive on the part of the Ministry of the Environment (MOE) which would like to bring "closure" to the matter of radiation exposure. Some committee and subcommittee members take them at face value as words from an authoritative international agency, but some who did not fully agree with the rushed summary of the second-round results (see this post) question validity of the report as well as transparency and integrity of UNSCEAR as an agency.
     In particular, attention was drawn to a transfer coefficient of iodine into the thyroid gland, which is set at 30% by ICRP. For the Fukushima report this coefficient was reduced by half to 15% owing to iodine-rich diet of the Japanese population, and consequently doses would be reduced in half. Members of the public and experts have questioned how reasonable this reduction is since modern Japanese diet is not always rich in iodine. 
     The very question was raised at the 45th session by a committee member Sakae Shibusawa of Tokyo University of Agriculture and Technology. It is a known fact that Subcommittee Chair Gen Suzuki leads a research team on the reconstruction of early internal doses funded by the MOE, and his team's work that reduced thyroid equivalent dose estimates (published paper,  2018 MOE reportcontributed to updated dose estimates by UNSCEAR. Suzuki said that his team determined a thyroid accumulation rate for the Japanese to be 18.6%, and UNSCEAR determined it to be 15%. Suzuki also stated that thyroid accumulation was not affected so much by the amount of iodine intake but more related to "genetic variations" in transport of iodine into the thyroid gland by NIS (sodium iodine symporter) and renal clearance. If the amount of iodine intake does not matter so much, why emphasize it so much? Furthermore, an assumption that the Japanese dietary habits include iodine-rich foods does not seem to be updated, failing to consider studies on modern dietary habits of the Japanese with lower iodine intake. (Added on September 19, 2022.)
     It's astonishing to think someone whose research team is actively contributing to reduced dose estimates is presiding over proceedings of the TUE Subcommittee where a relationship between thyroid cancer and thyroid doses is being investigated. Suzuki has declared that the Subcommittee would not take clinical and pathological data into consideration and focus on epidemiological analyses. When Suzuki was appointed Chair, it was not too hard to imagine what would eventually happen, but what is actually happening is worse than imagined.
     It should not be forgotten that the third-round data is still under evaluation, and the Oversight Committee has not come to a definitive conclusion that radiation health effects are unlikely. In truth, it is going to take many years to elucidate a cause of the increase in thyroid cancer in Fukushima, whether it be a true increase due to some factors such as radiation exposure or overdiagnosis. 
     The rushed summary of the second round raised many questions about transparency of data and credibility of its analysis (see this post). The first round was originally assumed to offer "baseline" data, to which the second round would be compared. Quietly the second round has essentially become part of the baseline in the English papers published by FMU (see this post). ("Quietly" because this is not a common perception at the Oversight Committee or the Subcommittee.) If the third-round data is too small, why not combine it with the second-round data with more thyroid cancer cases than the fourth round? This is unlikely because FMU has done everything to make any sign of dose response disappear so far. (Added on September 19, 2022.)
    
Summary of the results from the previous screening 
    Below is the summary of the previous screening results for the suspected/confirmed thyroid cancer cases. This information, already mentioned above except for the second round, can be difficult to locate in print. In particular, a breakdown of the "A2" assessment is only verbally reported during the Oversight Committee sessions. 

Definition
"A1": no ultrasound findings. 
"A2": ultrasound findings of nodules ≤ 5.0 mm and/or cysts ≤ 20.0 mm. 
"B": ultrasound findings of nodules  5.1 mm and/or cysts  20.1 mm.

    Having previous assessments of "A1" or "A2 cysts" means there were no precancerous lesions during the previous screening, i.e., cancer supposedly appeared since the previous screening. (Note: FMU claims that the cancerous lesions did not newly appear but already existed yet "invisible" during the previous screening.)
  • Second round (71 cases): 33 cases with A1, 32 cases with A2 (7 nodules and 25 cysts), 5 cases with B, 1 case previously unexamined
  • Third round (31 cases):  7 cases with A1, 14 cases with A2 (4 nodules and 10 cysts), 7 cases with B, 3 cases previously unexamined
  • Fourth round (39 cases): 6 cases with A1, 20 cases with A2 (6 nodules, 13 cysts, and 1 nodule & cyst), 9 cases with B, 4 cases previously unexamined
  • Fifth round (11 cases): 3 case with A1, 5 cases with A2 (4 cyst and 1 nodule & cyst),  2 cases with B, 1 case previously unexamined
  • Age 25 Milestone Screening (16 cases): 4 cases with A2 (1 nodule and 3 cyst), 3 cases with B, 9 cases previously unexamined

      

  

Fukushima Thyroid Examination May 2022: 226 Surgically Confirmed as Thyroid Cancer Among 274 Cytology Suspected Cases

 

Overview

    On May 13, 2022, the 44th session of the Oversight Committee for the Fukushima Health Management Survey (FHMS) convened online and in Fukushima City, releasing a new set of results (data up to September 30, 2021) from the fourth and fifth rounds as well as the Age 25 Milestone Screening of the Thyroid Ultrasound Examination (TUE).  The fifth-round data reported this time includes more details of the confirmatory examination results, and the first age & sex distribution graph was released for the Age 25 Milestone Screening. 

    The 44th session was the second session of the fifth term (August 2021-July 2023) of the Oversight Committee. (The first of two-year terms consisting of quarterly sessions commenced at the 11th session on June 5, 2013, after the departure of Shunich Yamashita amid controversy surrounding "secret meetings.")  It was unprecedented not only in the length of time that elapsed (seven months) since the previous session, but also in an unusual turnover of committee members at merely the second session: four members resigned, including Hokuto Hoshi who served as Chair for the five consecutive terms as well as Toshiya Inaba who as a fifth-term member and Vice Chair would have been a strong candidate to as new Chair. Everyone but Inaba has been replaced by someone from respective organizations, and the member roster stands at 17 for now.

   Hoshi's resignation was due to his political activity as a candidate in the summer 2022 election from the Fukushima electoral district for the House of Councillors (upper house) of the National Diet of Japan. His declaration for candidacy in mid-December 2021 meant the end of his reign as the Oversight Committee Chair, and it turns out he did resign as a committee member a month later. His resignation was a welcome news to some of the long-time audience faithfully following the Oversight Committee. (Hoshi would often diverge into lengthy monologues and even occasional emotional outbursts during these sessions, in addition to expressing displeasure and irritation by questions and comments at press conferences. None of these behaviors seemed appropriate as Chair.

     Hoshi has now been replaced by Noboru Takamura of Nagasaki University who is also serving his fifth term. Takamura is a known disciple of late Shigenobu Nagataki and infamous Shunichi Yamashita. It should not be forgotten that shortly after the 2011 Fukushima nuclear accident Fukushima Prefecture appointed Yamashita and Takamura to be radiation health risk management advisors. The pair went around Fukushima, downplaying potential health effects of radiation exposure in order to soothe people's fear. An excerpt below is from a Wall Street Journal article published on August 16, 2011.  (The article can be read here.)

On March 25, 2011 Takamura told about 600 villagers that they could continue to live safely in Iitate if they took precautions like wearing face masks outdoors and washing hands frequently, according to the village newsletter. Mr. Takamura said recently that radiation readings in the village were below 100 millisieverts — considered the threshold for health risk.

   Takamura is also known to have told Iitate Village residents that children could safely play outside up to 10 µSv/h of the ambient radiation. Besides his involvement with fieldwork in Kawauchi Village and Tomioka Town through respective Reconstruction Promotion Bases at Nagasaki University, Takamura is also curator of the Great Japan Earthquake and Nuclear Disaster Memorial Museum in Futaba Town, as described in this interview

     After Yamashita's well-publicized departure from Chair in March 2013 which coincided with the end of FY 2012, it seems that the Oversight Committee has come full circle with Takamura as Chair.

    On a separate note, only 3 months worth of new data as of September 30, 2021 was reported despite the lengthy pause of 7 months since the last session. The Oversight Committee is supposed to meet quarterly according to the implementation guidelines, but only 3 sessions each were held in 2019 and 2020, gradually widening the gap between compilation dates and report dates of the data. Quarterly sessions returned in 2021, and the data reporting was finally catching up, but now it's behind about 6 months even though other non-thyroid surveys were reporting the end-of-FY data as of March 31, 2021.

   At this time, an official English translation is still only available up to the 40th session of the Oversight Committee. The Radiation Medical Science Center of the Fukushima Health Management Survey (RMSC/FHMS) has rearranged its website, and the meeting materials are now available on this pageThe final results of the third round, released at the 39th session in August 2020, is also available in English on pages 2-20 of this report.

   
Highlights
  • The fourth round: 1 new case diagnosed as suspicious or malignant, and 3 new surgical cases. 
  • The fifth round: 3 new cases diagnosed as suspicious or malignant, and 2 new surgical cases.
  • Age 25 Milestone Screening: 4 new cases diagnosed as suspicious or malignant, and no new surgical cases.
  • Total number of suspected/confirmed thyroid cancer has increased by 8 to 274116 in the first round (including a single case of benign tumor), 71 in the second round, 31 in the third round, 37 in the fourth round, 6 in the fifth round, and 13 in Age 25 Milestone Screening.
  • Total number of surgically confirmed thyroid cancer cases has increased by 5 to 226 (101 in the first round, 55 in the second round, 29 in the third round, 32 in the fourth round, 3 in the fifth round, and 6 in Age 25 Milestone Screening,

The latest overall results including the "unreported" and cancer registry cases
    Please refer to the post on the May 2021 report regarding the details of "unreported" cases and cancer registry data.

    Official count, as reported in the summary document shown in the next section, is 274 suspected/confirmed and 226 surgically confirmed thyroid cancer cases. An addition of more recent "unreported" cases as well as "outside" cases discovered in cancer registry makes the count a little more complete with 333 cytologically suspected/confirmed and 269 surgically confirmed cancer cases. It should be noted that the actual number of cases is likely more than these as no exhaustive investigation has been and will be conducted by FMU to fully report all the cancer cases discovered outside the framework of the FHMS-TUE.


Summary on the current status of the TUE
    A seven-page summary of the first through fifth rounds as well as the Age 25 Milestone Screening, "The Status of the Thyroid Ultrasound Examination Results," lists key findings from the primary and confirmatory examinations as well as the surgical information. 
    Below is an unofficial translation of this summary which is not officially translated.


The fourth round
    For the still ongoing fourth round, originally scheduled from April 1, 2018 through March 31, 2020, only 31 more participated in the primary examination between July 1, 2021 and September 30, 2021, with an unchanged participation rate of 
62.3%. (Note: This is still below what the prior rounds registered (81.7% for the first round, 71.0% for the second round, and 64.7% for the third round), although it is slowly approaching the third round.)

    Only one person became newly eligible for the confirmatory examination, having received the "B" assessment in the primary examination. Ten newly participated in the confirmatory examination with 2 undergoing FNAC (fine-needle aspiration cytology), and one male, who was age 10 at the time of the 2011 nuclear accident, was diagnosed with suspected thyroid cancer. His third-round result was "B." He is from the FY 2018 municipality and a resident of Nakadori.

   Three (two cases from the FY 2018 municipalities and one from the FY 2019 municipalities) were newly confirmed with papillary thyroid cancer after undergoing surgery.  

    In summary, as of September 30, 2021, the number of suspected or confirmed thyroid cancer cases for the fourth round is 37, of which 32 have been surgically confirmed as papillary thyroid cancer. 

    The previous results from the third round are as follows: 25 with "A" (6 with A1, 13 with A2 cysts, 5 with A2 nodules, and 1 with A2 cysts and nodules), 9 with "B," and 3 with no prior result. 

The fifth round
    The fifth round targets 252,855 individuals, excluding about 21,000 born in FY 1996 (April 2, 1996 to April 1, 1997) and about 20,000 born in FY 1997 (April 2, 1997 to April 1, 1998) who are earmarked for the Age 25 Milestone Examination in FY 2021-2022. (It has previously been discussed how this exclusion skews age distribution graphs to the left.)

    The COVID-19 restrictions have had a significant impact on the progress of the fifth round which began in April 2020: school closures initially halted the school-based screening, and a burden on medical facilities reduced participation in the confirmatory examination. [Note: The fifth round was originally earmarked for FY 2020-2021 (April 2, 2020 to March 31, 2022), but the pandemic impact has forced an extension of the screening period by one year as described in this proposal: Elementary and middle school students from FY 2020 municipalities will undergo the TUE in FY 2020-2021, while FY 2021 municipalities will be pushed to FY 2022. For high school students, the TUE will be conducted in FY 2021-2022 with the exception of those who were already examined in FY 2020.]

     As of September 30, 2021, 45,860 participated in the primary examination, including 13,456 new participants, and its participation rate increased from 12.8% to 18.1%, still quite low. Participation rates by age group went up 30-50% at 31.3% in ages 8-11, 20.1% in ages 12-17, and 7.4% in ages over 18. The primary examination results are available for 38,136 (83.2%), and 458 (an additional 167 new cases) were assessed as "B," qualifying for the confirmatory examination. 

   Sixty-three newly participated in the confirmatory examination, 10 underwent FNAC, and 3 (1 male and 2 females) were diagnosed with suspected thyroid cancer. All three are residents of the FY 2020 municipalities. Age and tumor diameter data for the fifth round are available for the first time, and the age range at the time of the accident is shown to be 2 to 12 years, which means someone diagnosed in the fifth round was 2 years old at the time of the accident. Also newly reported were the results of blood tests and urinary iodine.

   Two from the FY 2020 municipalities have been confirmed with papillary thyroid cancer after undergoing surgery.

   In summary, as of September 30, 2021, the number of suspected or confirmed thyroid cancer cases for the fifth round is 6, of which 3 have been surgically confirmed as papillary thyroid cancer. 

   The previous results from the fourth round were released for the first time: 3 with "A" (1 with A1, 1 with A2 cysts, 1 with A2 nodules), 2 with "B," and 1 with no prior result. 

Age 25 Milestone Screening
    In the Age 25 Milestone Screening, each screening year targets a cohort turning 25 during each fiscal year, and the results are reported every 6 months. The most recent implementation schedule available in English is from September 2020, which was reported to the 41st session of the Oversight Committee and can be found here. (No one is supposed to undergo a "regular: TUE within 2 years of becoming eligible for the Age 25 Milestone Screening.) Although each fiscal-year screening is earmarked for those turning 25 during that fiscal year, participants can take part in the screening anytime up to the year before they become eligible for the Age 30 Milestone Screening. 

    Note: Transition of each FY birth cohort to the Age 25 Milestone Screening reduces a target population for the main TUE. This reduction began in the third round conducted during FY 2016-2017, which excluded the FY 1992 and 1993 cohorts in anticipation of the upcoming Age 25 Milestone Screening. With each FY birth cohort including about 22,000 individuals, this is a sizable reduction which continues as the TUE target population ages. For example, the target population has gone from 367,637 for the first round, to 381,237 for the second round (an increase here is due to the inclusion of those who were in utero at the time of the accident),  336,667 for the third round, 294,231 for the fourth round, and now 252,855 for the fifth round.

    The results reported this time are from the data up to September 30, 2021, and for the first time the age and sex distribution graph for suspected and confirmed cancer cases is included. Although this fiscal year cycle begins screening in those who were born in FY1996, the results from this cohort is not included here due to a limited number participants. Moreover in FY2022, those born in FY1992 became eligible to participate in the Age 30 Milestone Screening.

     Since the previously reported results as of June 30, 2021, 542 more participated in the primary examination, with total participants being 7,612,  A participation rate slightly increased by 0.6% to 9.3% which is still extremely low. 

    With an addition of 55 participants newly receiving "B" assessment in the primary examination, a total of 414 qualified for the confirmatory examination. Of 328 confirmatory examination participants including 89 added during this report period, 304 have the final results. After FNAC was conducted in 8 individuals (with a total FNAC cases of 25), 4 individuals (2 males and 2 females) were diagnosed with suspected thyroid cancer. Their prior screening results were: 1 with "A" (A2 cyst), 1 with "B," and 2 with no prior screening.

    Thus the number of suspected or confirmed thyroid cancer cases from the Age 25 Milestone Screening increased by 4 to 13. The results from the prior screening are: 2 with "A" (1 with A2 nodule, 1 with A2 cyst), 3 with "B" and 8 with no prior screening.

     No new surgical cases were added, and the number of surgically confirmed thyroid cancer cases remains at 6, including 5 papillary thyroid cancers and 1 follicular thyroid cancer. 

     Note: The FNAC results show a minimum tumor diameter of 6.2 mm, which is 3.2 mm smaller than last reported. This means that newly detected tumors are smaller and thus potential candidates for non-surgical active surveillance. No change in the number of surgical cases seems to support this scenario. (No evidence exists for active surveillance of noninvasive thyroid papillary microcarcinomas in pediatric population, but individuals in the Age 25 Milestone Screening are mostly in their late 20's at diagnosis.) 

    
Summary of the results from the previous screening 
    Below is the summary of the previous screening results for the suspected/confirmed thyroid cancer cases. This information, already mentioned above except for the second round, can be difficult to locate in print. In particular, a breakdown of the "A2" assessment is only verbally reported during the Oversight Committee sessions. 

Definition
"A1": no ultrasound findings. 
"A2": ultrasound findings of nodules ≤ 5.0 mm and/or cysts ≤ 20.0 mm. 
"B": ultrasound findings of nodules  5.1 mm and/or cysts  20.1 mm.

    Having previous assessments of "A1" or "A2 cysts" means there were no precancerous lesions during the previous screening, i.e., cancer supposedly appeared since the previous screening. (Note: FMU claims that the cancerous lesions did not newly appear but already existed yet "invisible" during the previous screening.)
  • Second round (71 cases): 33 cases with A1, 32 cases with A2 (7 nodules and 25 cysts), 5 cases with B, 1 case previously unexamined
  • Third round (31 cases):  7 cases with A1, 14 cases with A2 (4 nodules and 10 cysts), 7 cases with B, 3 cases previously unexamined
  • Fourth round (37 cases): 6 cases with A1, 19 cases with A2 (5 nodules, 13 cysts, and 1 nodule & cyst), 9 cases with B, 3 cases previously unexamined
  • Fifth round (6 cases): 1 case with A1, 2 cases with A2 (1 cyst and 1 nodule & cyst),  2 cases with B, 1 case previously unexamined
  • Age 25 Milestone Screening (13 cases): 2 cases with A2 (1 nodule and 1 cyst), 3 cases with B, 8 cases previously unexamined

      

  

Fukushima Thyroid Examination October 2021: 221 Surgically Confirmed as Thyroid Cancer Among 266 Cytology Suspected Cases


Overview

    On October 15, 2021, the 43rd session of the Oversight Committee for the Fukushima Health Management Survey (FHMS) convened online and in Fukushima City, releasing a new set of results (data up to June 30, 2021) from the fourth and fifth rounds of the Thyroid Ultrasound Examination (TUE).  The fifth-round data reported this time includes the confirmatory examination results. In addition, a corrected version of the results was released for the Age 25 Milestone Screening originally reported in July 2021. 

    The 43rd session was the first session of a new two-year term (August 2021-July 2023) for 18 committee members, including 6 new members. (Regrettably, a long-time committee member Fumiko Kasuga, who steadfastly advocated for release of more clinical information as well as inclusion of feedbacks from participants and their families, is no longer included.)  A roster for the Thyroid Examination Evaluation Subcommittee was also released, but there was no change. It was revealed that there was no target date for the release of an interim summary for the third round.

   At this time, an official English translation is available up to the 40th session of the Oversight Committee on the website (new URL as of April 1, 2022) for the Radiation Medical Science Center of the Fukushima Health Management Survey (RMSC/FHMS). The final results of the third round, released at the 39th session in August 2020, is finally available in English on pages 2-20 of this report.

   
Highlights
  • The fourth round: 3 new cases diagnosed as suspicious or malignant, and 2 new surgical cases. 
  • The fifth round: 3 new cases diagnosed as suspicious or malignant, and 1 new surgical case
  • Total number of suspected/confirmed thyroid cancer has increased by 6 to 266116 in the first round (including a single case of benign tumor), 71 in the second round, 31 in the third round, 36 in the fourth round, 3 in the fifth round, and 9 in Age 25 Milestone Screening.
  • Total number of surgically confirmed thyroid cancer cases has increased by 3 to 221 (101 in the first round, 55 in the second round, 29 in the third round, 29 in the fourth round, 1 in the fifth round, and 6 in Age 25 Milestone Screening,

The latest overall results including the "unreported" and cancer registry cases
    Please refer to the post on the May 2021 report regarding the details of "unreported" cases and cancer registry data.

    Official count, as reported in the summary document shown in the next section, is 266 suspected/confirmed and 221 surgically confirmed thyroid cancer cases. An addition of more recent "unreported" cases as well as "outside" cases discovered in cancer registry makes the count a little more complete with 325 cytologically suspected/confirmed and 264 surgically confirmed cancer cases. It should be noted that the actual number of cases is likely more than these as no exhaustive investigation has been and will be conducted by FMU to fully report all the cancer cases discovered outside the framework of the FHMS-TUE.


Summary on the current status of the TUE
    A six-page summary of the first through fifth rounds as well as the Age 25 Milestone Screening, "The Status of the Thyroid Ultrasound Examination Results," lists key findings from the primary and confirmatory examinations as well as the surgical information. 
    Below is an unofficial translation of this summary which is not officially translated.


The fourth round
    For the still ongoing fourth round, originally scheduled from April 1, 2018 through March 31, 2020, only 54 participated in the primary examination between April 2, 2021 and June 30, 2021, with an unchanged participation rate of 
62.3%. (Note: This is still below what the prior rounds registered (81.7% for the first round, 71.0% for the second round, and 64.7% for the third round), although it is slowly approaching the third round.)

    Having received the "B" assessment in the primary examination, 8 newly became eligible for the confirmatory examination. With mere 7 participants newly participating, the confirmatory examination increased its participation rate 0.1% to 73.4%. Out of 5 participants newly undergoing FNAC, 3 individuals (2 males and 1 female) were diagnosed with suspected thyroid cancer. Their third-round results were 1 with A2 cyst and 2 with B. Two males were ages 8 and 14 and the female was age 9 at the time of the 2011 nuclear accident. Both males are from the FY 2018 municipalities, and the single female is from the FY 2019 municipalities. Two are from Nakadori and one is from Hamadori. 

   Two more cases from the FY 2019 municipalities were newly confirmed with papillary thyroid cancer after undergoing surgery.  

    In summary, as of June 30, 2021, the number of suspected or confirmed thyroid cancer cases for the fourth round is 36, of which 29 have been surgically confirmed as papillary thyroid cancer. 

    The previous results from the third round are as follows: 25 with "A" (6 with A1, 13 with A2 cysts, 5 with A2 nodules, and 1 with A2 cysts and nodules), 8 with "B," and 3 with no prior result. 


The fifth round
    The fifth round targets 252,842 individuals, excluding about 21,000 born in FY 1996 (April 2, 1996 to April 1, 1997) and about 20,000 born in FY 1997 (April 2, 1997 to April 1, 1998) who are earmarked for the Age 25 Milestone Examination in FY 2021-2022. (The previous post discussed how this exclusion skews age distribution graphs to the left.)

    The COVID-19 restrictions have had a significant impact on the progress of the fifth round which began in April 2020: school closures initially halted the school-based screening, and a burden on medical facilities reduced participation in the confirmatory examination. [Note: The fifth round was originally earmarked for FY 2020-2021 (April 2, 2020 to March 31, 2022), but the pandemic impact has forced an extension of the screening period by one year as described in this proposal: Elementary and middle school students from FY 2020 municipalities will undergo the TUE in FY 2020-2021, while FY 2021 municipalities will be pushed to FY 2022. For high school students, the TUE will be conducted in FY 2021-2022 with the exception of those who were already examined in FY 2020.]

     As of June 30, 2021, 32,404 participated in the primary examination, including 8,992 new participants, and its participation rate increased from 9.3% to 12.8%, still quite low. Participation rates by age group are 24.2% in ages 8-11, 13.1% in ages 12-17, and 5.2% in ages over 18, showing a slow but steady progress of school-bases examination. The primary examination results are available for 24,882 (76.8%), and 291 (68 more) were assessed as "B" qualifying for the confirmatory examination. 

   One hundred seventy-five out of 291 have participated in the confirmatory examination, and 7 underwent FNAC which diagnosed 3 females with suspected thyroid cancer. Ages and average tumor diameter weren't available for these three, due to a small number of cases. Likely for the same reason, their prior screening results were also not released. Two are from the FY 2020 municipalities and one is from the FY 2021 municipalities. 

   The single case from the FY 2021 municipalities has been confirmed with papillary thyroid cancer after undergoing surgery.


Age 25 Milestone Screening results corrected
    
    No new results were released for the Age 25 Milestone Screening, but the confusion on the prior screening result of the single new case reported last time was clarified. She tested as "B" in the prior screening as reported verbally, and a corrected version of the results was released. Also, the single A2 case was confirmed to be nodule. 

   The results from the prior screening for 9 suspected or confirmed cases are: 1 with A2 nodule, 2 with "B," and 6 with no prior screening.

    
Summary of the results from the previous screening 
    Below is the summary of the previous screening results for the suspected/confirmed thyroid cancer cases. This information, already mentioned above except for the second round, can be difficult to locate in print. In particular, a breakdown of the "A2" assessment is only verbally reported during the Oversight Committee sessions. 

Definition
"A1": no ultrasound findings. 
"A2": ultrasound findings of nodules ≤ 5.0 mm and/or cysts ≤ 20.0 mm. 
"B": ultrasound findings of nodules  5.1 mm and/or cysts  20.1 mm.

    Having previous assessments of "A1" or "A2 cysts" means there were no precancerous lesions during the previous screening, i.e., cancer supposedly appeared since the previous screening. (Note: FMU claims that the cancerous lesions did not newly appear but already existed yet "invisible" during the previous screening.)
  • Second round (71 cases): 33 cases with A1, 32 cases with A2 (7 nodules and 25 cysts), 5 cases with B, 1 case previously unexamined
  • Third round (31 cases):  7 cases with A1, 14 cases with A2 (4 nodules and 10 cysts), 7 cases with B, 3 cases previously unexamined
  • Fourth round (36 cases): 6 cases with A1, 19 cases with A2 (5 nodules, 13 cysts, and 1 nodule & cyst), 8 cases with B, 3 cases previously unexamined
  • Age 25 Milestone Screening (9 cases): 1 case with A2 (nodule), 2 cases with B, 6 cases previously unexamined
      
  

Fukushima Thyroid Examination September 2022: 236 Surgically Confirmed as Thyroid Cancer Among 284 Cytology Suspected Cases

   Overview      On September 1, 2022,  t he 45th session of the Oversight Committee  for the  Fukushima Health Management Survey  (FHMS) co...