Fukushima Thyroid Examination June 2018: 162 Surgically Confirmed as Thyroid Cancer Among 198 Cytology Suspected Cases

For more detailed information on the Fukushima Thyroid Examination itself, see the September 2017 fact sheet (long version, or e-published PDF)

Highlights: 

• The third round: 2 cases newly diagnosed as suspicious or malignant, and 2 new  cases surgically confirmed.
• Total number of suspected/confirmed thyroid cancer is now 198 (excluding a single case of benign tumor; 115 in the first round, 71 in the second round, and 12 in the third round).
• Total number of surgically confirmed thyroid cancer cases has increased by 2 to 162 (101 in the first round, 52 in the second round, and 9 in the third round)
• Hiroki Shimura replaces Akira Ohtsuru as the new Director of the Thyroid Ultrasound Examination.
• "Age 25 Milestone Screening" results released for those born in FY1992. (Shown in the bottom part of this post.)

The latest overall results:

On June 18, 2018, the 31st Oversight Committee for Fukushima Health Management Survey (FHMS) convened in Fukushima City, Fukushima Prefecture. Among other information, the Oversight Committee released the latest results (as of March 31, 2018) of the third round of the Thyroid Ultrasound Examination (TUE). For the first round, a 3-page summary of the final results was released. For the second round, the final results were previously released at the Eighth Thyroid Examination Assessment Subcommittee held on November 30, 2017, but it hasn't been translated into English. Also, a FY2017 update to the final results of the second round was released. (Final results for the first round have been updated at the end of each fiscal year, March 31.) Official English translation of the results is posted here. (As of July 20, 2018, only the third round results have been translated into English.)

Since the 29th Oversight Committee held on December 25, 2017, Fukushima Medical University (FMU) has released a 4-page summary of all 3 rounds conducted so far, "The Status of the Thyroid Ultrasound Examination." This summary has proven quite useful, listing key findings from the primary and confirmatory examinations as well as the surgical information. In particular, any update to the number of surgical cases is reflected in this summary before the information is compiled in the fiscal year update. There is no official English translation of this summary, but here's an unofficial translation. 

Status of the Thyroid Ultrasound Examination (June 18, 2018) by Yuri Hiranuma on Scribd

Key points from the Oversight Committee:

New Director of the TUE

It was a surprise not to see Akira Ohtsuru at the Oversight Committee session. Ohtsuru began to report the results of the TUE at the 19th Oversight Committee on May 18, 2015, replacing Shinichi Suzuki, a thyroid surgeon at FMU. It was explained at the time that Suzuki was to concentrate on the clinical (surgical) aspect of the TUE, but it definitely led to a loss of access to a first-hand account from the surgeon directly involved with medical care of the thyroid cancer patients. Unlike Suzuki, Ohtsuru would not slip out heavily guarded clinical information. Actually, unlike Suzuki's smooth talking, it was apparently difficult to hear Ohtsuru even in the room even though he used a microphone. Now, a baton has been passed to Hiroki Shimura, Chairman of Department of Laboratory Medicine at FMU. This time there was no problem making out what was being said.

Participation rates

The primary examination participation rates have been declining with each successive round of the TUE: 81.7% for the first round, 71.0% for the second round, and 64.3% for the third round. In particular, a participation rate for age 18 or older (age at screening) has gone from already low 25.7% in the second round to even lower 15.9% in the third round. Participation rates for the confirmatory examination have also been declining from 92.9% in the first round, 84.1% in the second round, and 58.7% in the third round which is still ongoing.

Cytology rates

There have been repeated questions regarding declining rates of cytology among participants of the confirmatory examination: 39.6% in the first round (63.9% in FY2011, 44.3% in FY2012, and 29.8% in FY2013), 14.8% in the second round (19.1% in FY2014 and 9.2% in FY2015), and 5.6% in the third round (6.2% in FY2016 and 3.8% in FY2017). Note that the confirmatory examination for FY2016 and FY2017 is still ongoing.

The decline in successive rounds (39.6% to 14.8% to 5.6%) was previously explained to reflect some participants repeating the confirmatory examination and not necessarily requiring repeat cytology. A big drop during the first round from FY2011 to FY2013 has been attributed to a more chaotic situation in the first year of the first round leading to cytology performed with abundance of caution. This time Shimura supplemented the explanation by stating that as examiners gained more experience, they were more comfortable with determining the need for cytology for each case. This statement drew multiple questions especially from members of the press regarding if the examiners were strictly adhering to the diagnostic guidelines. 

The TUE support program

A fiscal report on the TUE support program sheds some light on the existence of several thyroid cancer cases not included in the official tally. (See the section below for background information.) This program offsets out-of-pocket medical expenses (30% copay) incurred due to participation in the TUE, if all 3 eligibility criteria are met: 1) participation in the TUE, 2) requiring a follow-up observation or medical treatment for conditions such as thyroid nodular lesions if they were detected during the TUE confirmatory examination, and 3) receiving or having received outpatient and/or inpatient medical care at medical facilities authorized to conduct the TUE confirmatory examination or other medical facilities referred by such authorized facilities. The TUE support program excludes those receiving full medical assistance such as those ages 18 and under living in Fukushima Prefecture or those on welfare.

The TUE support program began on July 10, 2015. Between FY2015 and FY2017, 313 payments were made to 233 individuals (ages 18-25), including 82 surgical cases (ages 18-23). Post-operative pathological diagnoses included 77 cases of thyroid cancer (76 cases of papillary thyroid cancer and 1 case of poorly differentiated thyroid cancer) and 5 cases of thyroid conditions other than cancer, such as follicular adenoma. Of 77 cases of thyroid cancer, 72 were diagnosed directly during the confirmatory examination, 3 were diagnosed during a clinical follow-up for a non-cancer thyroid condition after the confirmatory examination, and 2 were diagnosed totally outside the TUE system without participating in the confirmatory examination. 

Thyroid cancer cases diagnosed outside the framework of the TUE

It has been known that the official tally of thyroid cancer cases is far from complete partially due to a loophole in the study design that is not conducive to a compilation or release of "clinical" information once the suspicious cases move from the specially-funded TUE to regular medical care during the confirmatory examination. That is, if a suspected cancer is diagnosed directly during the confirmatory examination, it is included in the official report. However, cases might not need cytology urgently but warrant closer follow-ups such as every 6 months to 1 year rather than the next screening cycle 2 years later. Such cases are moved to a "clinical follow-up track" under the national health insurance, and FMU has been extremely reluctant to release detailed clinical information citing privacy protection. (This is explained in the Transparency and Integrity of Data section of the September 2017 fact sheet.)

In some cases, participants might voluntarily go outside the framework of TUE either from the beginning or the middle of the screening. This happens when they decide to undergo the primary and/or confirmatory examination at non-FMU medical facilities for various reasons—for instance, physical (evacuation or relocation due to schooling/jobs) and/or psychological (distrust). One such case, discussed in this post, revealed an existence of a cancer case in a 4-year-old boy (age at the accident time).

Due to repeated requests from the press as well as the committee members to gather cancer cases diagnosed outside the TUE framework, FMU has been conducting a study since late 2017, investigating how many of the surgical cases at FMU are actually from the "clinical follow-up track." No report was made on this matter at this Oversight Committee session. This "study" is being conducted by Thyroid and Endocrine Center in Fukushima Global Medical Science Center at FMU. It should be noted this study will not collect any information on surgical cases at non-FMU facilities.

As described in the section above, the TUE support program fiscal report reveals 3 thyroid cancer cases diagnosed in the clinical follow-up track as well as 2 cases diagnosed totally outside the TUE system. Because the TUE support program is only offered to those aged 18 and above, it gives no information on any clinical follow-up or non-TUE cancer cases in children younger than age 18. We know at least one such case as in the then 4-year-old mentioned earlier. 

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The first round results

From the FY 2016 supplemental report with data as of March 31, 2017. (Summary report with data as of March 31, 2018, only shows the total results, not by fiscal year cohorts. However, for the content shown below, information remained the same between 2017 and 2018.)

The second round results

No change since the last Oversight Committee meeting on March 5, 2018.

The third round results

Two new suspicious/malignant cases were diagnosed from the FY 2016 cohort: one female (age 11 in March 2011) and 1 male (age 16 in March 2011). They both reside in Naka-dori municipalities. One had an A1 assessment in the second round, and the other never participated in the second round.

Age 25 Milestone Screening results

After reaching age 20, the TUE transitions to screening every 5 years at a "milestone" of ages 25, 30, 35, 40, etc. The third round results this time included a separate report on the first group of "Age 25 Milestone Screening," 22,653 individuals born in FY 1992 (April 1, 1992 through March 31, 1993).

Table 1 shows that the participation rate of the primary examination is extremely low at 8.4%. Nearly one-third of 1,846 whose primary examination results are complete had not participated in previous TUE, shown as 577 "non-participants" in Table 3. It should be noted that nearly one-third of 80 subjects with "B" assessment requiring confirmatory testing came from these 577 subjects who never participated in the TUE.

Table 4 indicates that 41 or only half of 80 underwent required confirmatory examination. In 31 subjects with completed confirmatory examination, none underwent FNAC or reclassified as A1 or A2. This suggests that they likely have some type of thyroid conditions that are not cancerous but require clinical follow-ups. 

According to Shimura, those missing the Age 25 Milestone Screening can be screened before the Age 30 Milestone Screening.

Table 1. Screening test (primary examination) coverage as of March 31, 2018

Table 2. Number and proportion of children with nodules/cysts as of March 31, 2018

Table 3. Comparison with the prior examination, as of March 31, 2018

Note 1: Top line refers to the results of the prior examination for confirmed results of the Age 25 Milestone Screening.

Note 2: Top line refers to the breakdown of the Age 25 Milestone Screening results in a given category of the prior examination results. Bottom line shows the proportion in %.

Table 4. Confirmatory examination coverage and results as of March 31, 2018