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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%.

*****
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). 

*****
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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Wednesday, December 24, 2014

Fukushima Thyroid Examination: Four Suspected of Cancer in Second Screening--These Children Had Normal Exam Results in First Screening

As with some of the previous committee meetings, thyroid cancer information was apparently leaked to the media the day before the 17th Prefectural Oversight Committee Meeting for Fukushima Health Management Survey, scheduled for December 25, 2014. Since the English edition of the Kyodo news article contained very little information, just as the online Japanese news articles, all based on the same Kyodo post, the paper edition of the Fukushima Minyu post was transcribed and translated as below. (See below the translation for the actual images of the post in the paper edition).

*****
From the December 24, 2014 article in the paper edition of Fukushima Minyu. (The online edition only includes the first three paragraphs and the first sentence of the fourth paragraph).

Thyroid Examination: Four Suspected of Cancer in Second Screening--These Children Had Normal Exam Results in First Screening

In the thyroid examination conducted in all children in Fukushima Prefecture in order to investigate the effects of radiation as a result of the Tokyo Electric Fukushima Daiichi nuclear power plant (NPP) accident, officials revealed on December 23rd that 4 children whose first screening was “normal” were diagnosed with suspect thyroid cancer in the second screening. It is to be reported at the Prefecture Oversight Committee to be held in Fukushima City on December 25th.

If these cases are confirmed to be thyroid cancer, they will become the first cases where the increase in cancer is confirmed after the NPP accident.

Fukushima Medical University (FMU), in charge of the screening examination, will hurry to confirm the diagnoses and carefully ascertain whether these cases were caused by the effects of radiation exposure.

Occurrence of pediatric thyroid cancer cases skyrocketed 4-5 years after the Chernobyl NPP accident in 1986. Because of this, FMU considers the results of the first screening, during the three years after the accident, as baseline data with no radiation effects. FMU plans on investigating the effects of radiation by comparing any increase of cancer cases from the second screening onward.

The first screening targeted approximately 370,000 residents who were 18 and younger at the time of the accident. The second screening targets approximately 385,000 residents, including children born in the first year after the accident. In each screening, ultrasound is used to examine the size and shape of thyroid mass, which is classified as “A1,” “A2,” “B” and “C” assessment categories, in the ascending order of severity. “B” and “C” assessment categories go onto secondary examination with a detailed blood test as well as a cytological biopsy.

According to officials, 4 people who were diagnosed with suspect cancer are men and women whose ages were in the 6-17 range at the time of the accident. In the first screening, they had “normal” test results, with 2 in “A1” and the other 2 in “A2” assessment categories. The four participated in the second screening, which began in April 2014, where they were classified in the “B” category and diagnosed with “suspect cancer” during the secondary examination. The tumor size varies from 7 to 17.3 mm.

External exposure dose estimation for the first four months after March 11, 2011 was available for the three of the four, with the maximum being 2.1 mSv. The places of residence for the four [at the time of the accident] included Okuma Town, Fukushima City, Date City and Tamura City.

In addition, it was newly revealed that the number of children who were confirmed with cancer during the first screening went from 57, as of August 2014, to 84, increasing by 27. The number of children with suspect cancer is now 24 (46 as of August).


Images of the article in the paper edition courtesy of @fukushima_info.
The original Japanese transcript can be found here.





Saturday, November 29, 2014

Details of Fukushima Thyroid Cancer Surgical Cases

This is a compilation of the most current information on Fukushima thyroid cancer surgical cases from 3 different sources: 
  1. November 11, 2014 Thyroid Examination Evaluation Subcommittee meeting
  2. November 14, 2014 Japan Thyroid Association meeting
  3. August 28, 2014 Japan Society of Clinical Oncology meeting

Due to the span of the time amongst these 3 sources, they have different numbers for the cases of thyroid cancer. For clarification, the most updated summary of the thyroid cancer cases is presented first. 


********************************************************************************************************
Summary of Fukushima thyroid cancer cases as of November 2014

Number of cases suspected or confirmed of thyroid cancer = 104
Cases that had surgery = 58
Cases confirmed of thyroid cancer = 57 (1 of 58 turned out to be benign nodule)

55 of 58 cases were operated on at Fukushima Medical University (FMU)
  • 1 turned out to be benign nodule
  • 52 cases of papillary thyroid cancer
  • 2 cases of poorly differentiated thyroid cancer 

Pre-operative diagnosis: 
42 cases (78%) had pre-surgical tumor diameter > 10 mm
12 cases (22%) had pre-surgical tumor diameter 10 mm:
  • 3 suspected to have lymph node or distant metastasis.
  • 7 cases with proximity to trachea or recurrent laryngeal nerve, or extrathyroidal extension 
  • 2 cases of voluntary surgery despite recommendation of non-surgical follow-up

Overall, 17 cases (31%) had lymph node metastasis and 2 cases (4%) had distant metastasis to the lungs

Operative methods:
5 cases (8%) had total thyroidectomy
49 cases (91%) had hemithyroidectomy
All 54 cases had lymph node dissection

Post-operative pathological diagnosis:
15 cases (28%) had tumor diameter ≤ 10 mm, and 3 (6%) of them had no lymph node metastasis or distant metastasis (pT1a pN0 M0)          
37% (?20 cases?) had extrathyroidal extension
74% (?40 cases?) were positive for lymph node metastasis
No post-operative complications (post-surgical hemorrhage, permanent paralysis of recurrent laryngeal nerve, hypoparathyroidism, or hypothyroidism after hemithyoidectomy) observed.

Note: 2 cases of lung metastasis were papillary thyroid cancer cases.

*****
Thyroid Examination Evaluation Subcommittee

Information that was released by Shinichi Suzuki at the Thyroid Examination Evaluation Subcommittee meeting held on November 11, 2014

Regarding Surgically Indicated Cases

Three years have passed since the disaster struck. Of 1,848 subject what underwent secondary examination up to June 30, 2014, 485 had cytological examinations. Suspicious or malignant cases totaled 104, and 58 of them were already operated on.

Surgeries on 55 of 58 cases were conducted at the Division of Thyroid and Endocrine Surgery, Fukushima Medical University. 3 cases were operated on at other facilities. As 1 of 55 cases turned out to be benign nodule post-operatively, only the 54 thyroid cancer cases were considered there.

According to the pathological evaluation, 52 cases were papillary cancer, and 2 were poorly differentiated thyroid cancer.

In pre-operative diagnosis, 42 cases (78%) had tumor diameter > 10 mm. and 12 (22%) were ≤ 10 mm in diameter. Also, of the 12 cases with tumor diameter of ≤10 mm, 3 (5%) were suspected to have lymph node metastasis and/or distant metastasis. 9 (17%) cases were not suspected to have lymph node or distant metastasis (cT1acN0cM0).

Of these 9 cases, 7 were suspected to be close to the trachea or the recurrent laryngeal nerve, or have extrathyroidal extension. The remaining 2 cases were operated on based on patients’ wishes, despite the recommendation of non-surgical follow-up.

Furthermore, 17 cases (31%) were positive for lymph node metastasis, and 2 cases (4%) were suspected of multiple lung metastasis.

Surgical methods included total thyroidectomy in 5 cases (9%), and hemithyroidectomy in 49 cases (91%). Lymph node dissection was conducted in all cases, with 67% limited to the central compartment and 33% including lateral compartment. As much as possible, small-size incisions of 3 cm were used.

Post-surgical pathological diagnosis revealed 15 cases (28%) with tumor diameter ≤ 10 mm, and 3 (6%) of them had no lymph node or distant metastasis (pT1a pN0 M0). Extrathyroidal extension, pEX1, was seen in 37%, and 74% was positive for lymph node metastasis. No post-operative complications (post-surgical hemorrhage, permanent paralysis of recurrent laryngeal nerve, hypoparathyroidism, or hypothyroidism after hemithyoidectomy) were observed.

*****
The 57th Annual Meeting of the Japan Thyroid Association
November 14, 2014

Identification of  gene clusters related to initiation of thyroid cancer and elucidation of pathogenesis in children and young adults

Shinichi Suzuki, Toshihiko Fukushima, Michiko Matsuse, Yudai Hirata, Hirokazu Okayama 1, Chiyo Okouchi 1, Toshiyuki Monma 2, Hiroshi Mizunuma 1, Satoshi Suzuki, Noritato Mitsutake 3, Shunichi Yamashita 3
Department of Thyroid and Endocrinology, School of Medicine, Fukushima Medical University, Department of Organ Regulatory Surgery, Fukushima Medical University, Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University

There has been an increase in the number of pediatric and young adult patients diagnosed with thyroid cancer due to the advance in diagnostic ultrasound technology and implementation of pediatric thyroid ultrasound screening. However, pathogenesis relating to initiation and development of these cancers is yet to be fully understood. As  it is anticipated the number of cases will increase in the future, we will identify gene clusters related to cancer initiation and elucidate the mechanism of pathogenesis in order to reveal biological features of these cancers. In this study, we investigated the gene clusters known to be related to thyroid cancer initiation.

Study subjects: 24 surgical cases (male:female = 1:2, average age 17.9 years (9-22 years)) in children and young adults. 23 cases were papillary thyroid cancer and 1 was follicular cancer. (Note: The actual presentation referred to 23 cases of papillary thyroid cancer and 1 case of poorly differentiated thyroid cancer).

Method: DNA and RNA were extracted from excised tumor tissues and analyzed with direct sequencing and PT-PCR. Mutation in BRAF, K-, N-, and H-RAS and rearrangement in RET/PTC1 and RET/PTC3 were investigated.

Results: 67% was positive for BRAF mutation. Also, 12.5 % had rearrangement of RET/PTC1, but no mutation was found in RET/PTC3, K-, N-, and H-RAS.


Information from the transcript of the presentation by Shinichi Suzuki

23 cases were papillary thyroid cancer (19 cases of classical type, 1 case of follicular variant, and 3 cases of cribriform-morular variant or CMVPTC), and 1 case was poorly-differentiated thyroid cancer.

23 patients were from the Fukushima Health Management Survey Thyroid Examination, and 1 case of a 22-year-old female was unrelated to the survey.

Genetic analysis results:

RET/PTC1: positive in 3 cases or 12.5%average age 17.8 years)
ETV6/NTRK3: positive in 1 case or 4.2 (16-year-old female
BRAF (known to be common in adults): positive in 18 cases or 67%average age 18 years
No RET/PTC3, K-, N-, H-RAS, or TRK detected.
5 cases (all females, average age 16.7 years) were negative for RET/PTC1, BRAF, or ETV6/NTRK3.
The patient unrelated to Fukushima Health Management Survey, a 21-year-old female, was RET/PTC1 positive.

BRAF, RET/PTC1 and ETV6/NTRK3 cases were all classical type papillary thyroid cancer.
Five all-negative cases included 1 case of follicular variant papillary thyroid cancer, 1 case of poorly-differentiated cancer, and 3 cases of cribriform-morular variant papillary thyroid cancer (CMVPTC). CMVPTC cases are under investigation for APC genetic mutations which are known to be causative. All 3 CMVPTC cases have family history.
Five all-negative cases had slightly larger tumor diameter than others. These 5 cases were the only cases undergoing total thyroidectomy.

BRAF positive cases are said to be aggressive. RET/PTC1 tends to be seen in older children and associated with cases unrelated to radiation exposure. RET/PTC3 is seen in younger children, and seen frequently in Chernobyl, although it is not considered to be the definitive oncogene for radiation-induced PTC. It is commonly thought gene rearrangements are more frequently seen in children, whereas point mutations are seen more in adults.

As a conclusion, BRAF, the genetic mutation detected most frequently, is what is usually seen in typical adult PTC. It is highly possible that cases which may not have been detected if it weren’t for the thyroid ultrasound screening are being discovered in children and young adults as a result of the screening.


Note 1: Three cases of cribriform-morular variant papillary thyroid cancer are not consistent with the information from the August 2014 meeting of Japan Society of Clinical Oncology below, showing 3 cases of diffuse sclerosing variant papillary thyroid cancer. It is likely the pathological diagnosis was updated after an outside review.

Note 2: Suzuki’s presentation of these details outside the Thyroid Examination Evaluation Subcommittee, especially before the information was shared with the Subcommittee and the public, created controversy as to the handling of data. Suzuki claims the study was accepted by the ethics committee at Fukushima Medical University, but the thyroid examination itself is conducted with the money provided by the central government to Fukushima Prefecture, and the data belongs to the prefecture and the residents. Suzuki has a track record of not revealing the data to the Thyroid Examination Evaluation Subcommittee or the Prefectural Oversight Committee for Fukushima Health Management Survey before presenting it at an academic meeting in August 2014, as described below.

Note 3: This meeting was closed to media due to the decision of the conference chair, based on the wishes of some of the presenters.

Note 4: Shigenobu Nagataki, a mentor to Shinichi Yamashita, revealed the following information during the questions and answers session:

Shigenobu Nagataki was invited to do a presentation called “Fukushima Daiichi Accident and Thyroid Cancer” at “Meet-the-Professor Workshop” on October 30, 2014 at the 84th Annual Meeting of theAmerican Thyroid Association.  

He was asked by thyroid specialists attending the meeting if nodule sizes were the only thing determined in this unprecedented, large-scale screening. Participants wanted to know how many had Graves’ disease, autoimmune thyroiditis, goiter, etc. [Note: Fukushima Health Management Survey has not released hardly any data regarding non-cancer thyroid diseases]. Nagataki referred to patient privacy in disclosing such information, but he was told patient privacy meant such things as patients’ names and had nothing to do with how many patients had Graves’ disease. [Note: Fukushima Medical University cites patient privacy when refusing to disclose details of their findings]. They asked him there must be a rough estimate of non-cancer thyroid diseases made by thyroid specialists conducting ultrasound screening. Nagataki told them he would get back to them in writing as he didn’t know what to say.


*****

The 52nd Annual Meeting of Japan Society of Clinical Oncology
August 28-30, 2014

Organ Specific Symposium 03, August 28, 2014  10:00-12:00
OS3-5 “Treatment of Pediatric Thyroid Cancer in Fukushima”
Shinichi Suzuki
Division of Thyroid and Endocrinology, School of Medicine, Fukushima Medical University

Pediatric thyroid cancer has been considered rare, consisting approximately 1-2% of all thyroid cancer. They might appear to be advanced at first sight, with lung metastasis or widespread lymph node metastasis discovered at the time of diagnosis, but long-term survive is known to be extremely good.

After the Fukushima Daiichi nuclear power plant accident following the Great East Japan earthquake and tsunami on March 11, 2011, Fukushima Prefecture was burdened with the prospect of faces long-term radiation health effects. Fukushima Health Management Survey was launched in Fukushima Prefecture, with one of the surveys being thyroid ultrasound examination of residents who were children at the time of the accident. Initial Screening has already completed, and thyroid cancer cases have been discovered. We report our experience in treating these asymptomatic pediatric thyroid cancers detected through ultrasound screening, unlike the usual symptomatic thyroid cancer.

Study subjects are 269,354 children (participation rate 80.8%) who underwent primary examination from October 2011 to December 31, 2013. Of these, 1796 required secondary examination, and 75 of them were diagnosed with malignant or suspicious tumor as a result of fine-needle aspirational biopsy. 34 already had surgery, and 33 were confirmed to have thyroid cancer. We are reporting here on the 31 cases operated on in our department.

Average age at the time of surgery is 16.4 (9-20) years,  the male to female ratio is 14:17, and 9 cases were from Fiscal Year 2011 (from 13 municipalities designated by the government to be evacuation zone), and 22 cases were from Fiscal Year 2011.

Average tumor diameter at the time of surgery was 14.9 mm (6-13 mm). Pre-operative diagnosis revealed 22 cases of T1 (7 T1a and 15 T1b1), 7 cases of T2, and 2 cases of T3. 19 cases were N0, 12 cases were N1 (4 N1a and 8 N1b), 29 cases of M0 and 2 cases of M1 (lungs). Surgical method was 28 cases of hemithyroidectomy and 3 cases of total thyroidectomy, and lymph node dissection included 19 cases of central compartment dissection, and12 cases of lateral compartment dissection. Post-operative diagnosis revealed 24 cases of papillary thyroid cancer (usual type), 3 cases of follicular-type papillary thyroid cancer, 3 cases of diffuse sclerosing papillary thyroid cancer, and 1 case was suspicious of poorly differentiated thyroid cancer.  21 cases of pT (9 cases of pT1a, 12 cases of pT1b), 23 cases of pT2, 7 cases of pT3 (EX1), 7 cases of pN0, and 24 cases of pN1 (12 pN1a and 12 pN1b). Two cases with pre-operative suspicion of  M1 (lungs), which had the Tg level in the blood dropping below detection range after total thyroidectomy, will be scheduled for either CT scan of lungs or I131 scintigraphy.

In all cases, intraoperative monitoring of the recurrent laryngeal nerve was conducted using NIM. Surgical incision for neck dissection was limited to small skin incisions of 3 cm in the central compartment dissection and 3-5 cm in the lateral compartment dissection. No paralysis of the recurrent laryngeal nerve or hypoparathyroidism was observed.