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 both 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 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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