FMU Thyroid Ultrasound Surveys in Fukushima Prefecture

FMU Thyroid Ultrasound Surveysin Fukushima Prefecture

Shin-ichi Suzuki MD, PhDProfessor and Chairman Department of Thyroid and EndocrinologyDirector Department of Thyroid Ultrasound Examination, Radiation Medical Science Center for the Fukushima Health Management Survey, Fukushima Medical University School of Medicine

Introduction 1• Thyroid cancer is well known good

prognosis among all solid neoplasms. • External (X-ray, γ-) radiation and internal

exposure to radioiodine impose increased thyroid cancer risk.

• Risk has strong inverse correlation with age at exposure; highest risk is in youngest children.

• Thyroid cancer in children is usually rare.

Radiation Medical Science Center for the FHM survey, FMU

Introduction 2

After the TEPCO-Fukushima Daiichi Nuclear Power Plant accident on March 11, 2011, the publics in Japan had a particular concern about the increased risk of childhood thyroid cancer in similar to Chernobyl.

After the Chernobyl nuclear accident in 1986, childhood thyroid carcinoma had a great increase in Belarus and Ukraine, as a consequence of the exposure to iodine radioactive fallout.


Introduction 3• We decided to perform thyroid ultrasound

examinations (TUE) on all children in Fukushima prefecture as one of the detailed surveys of a Fukushima Health Management (FHM) survey.

• The increase in thyroid cancer was reported to start 4 or 5 years after Chernobyl accident.

• Therefore, we started TUE to know the current thyroid status in Fukushima within first 3 years after disaster.



Flow Chart of Thyroid Ultrasound Examination

Next Exam.2014

Surgical Treatment

, etc.Benign

First screening (primary examination)

Secondary screening (Confirmatory examination)Precise US examination, Blood and Urinary analyses

Malignant

CriteriaFollow-

up

YesNo

FNAC Informed consent,Furtherexamination

ＨＩＶＩＳＩＯＮ　Ａｓｃｅｎｄｕｓ

LOGIQ e Expert

Portable US machineNodule/Cyst

Noblus


Judgment Interpretation recommend

A Within normal

(A1) No nodule and/or Cyst* next primary examination

(A2)Nodule with ≤5.0mm** or/andCyst with ≤20.0mm

next primary examination

B Nodule with ≥5.1mm or/andCyst with ≥20.1mm

confirmatoryexamination

C Required immediately examination

urgentconfirmatoryexamination

Diagnostic Criteria

*Mixed cystic-solid nodule is include the category of “nodule”.**Some test results A2 may be classified as B when clinically indicated.


Criteria of Cyst

Mixed cystic-solid nodule is include the category of “nodule” in this survey. Because mixed type occurs in cancer.

Multiple Cysts with colloid clot(Colloid cysts) which is confirmedby the comet sign, is diagnosed by US examination without FNAC.

In this survey, the category of “ cyst “ is simple cyst or colloid cyst that means normal.


Schedule of Thyroid Ultrasound Examination (TUE)

The ＴＵＥ is performed one by one at the time of the Nuclear accident from the residents of the area which was high as for the atmospheric dose of radioactivity.

The full-scale survey will then continue every two years until the age of 20, and every 5 years thereafter for the reminder of the subjects life.


• Preliminary survey*: 360,000 from October 2011 to March 2014 1st survey: from October 2011 to March 2012

2nd survey: from April 2012 to March 2014*: This time is considered that radiation-induced thyroid disease do not appear yet .

• Full scale survey: 360,000 from April 2014 to end of March 2016

①

②

③

③②①

②→③13 municipalities in the nationally designated evacuation zones

Primary examination of thyroid ultrasound examination (TUE) from Oct 9, 2011 at the Fukushima Medical University Hospital


Results of First Screening of Preliminary Survey from October 9, 2011 to the End of 　 December 　

2013

A1; 134805; 53.0%

A2; 117679; 46.3%

B; 1795; 0.7% C; 1; 0.0%

A1A2BC

N=254,280

Participants; 269354; 80.8%

Non-partic-ipants, 64049, 19.2%


a b c

(0.7) 1 (0.0)( 94.4) 134,805 (53.0) 117,679 (46.3) 1,795Total 333,403 269,354 (80.8) 6,147 254,280

40,668 (55.2) 591 0 (0.0)FY 2013 122,373 88,554 (72.4) 293 73,666 ( 83.2) 32,407 (44.0) (0.8)

61,985 (44.6) 986 (0.7) 1 (0.0)FY 2012 163,264 139,239 (85.3) 3,905 139,092 ( 99.9) 76,120 (54.7)

(0.5) 0 (0.0)(63.3) 15,026 (36.2)FY 2011 47,766 41,561 (87.0) 1,949 21841,522 ( 99.9) 26,278

Screening test coverage as of 31 December 2013 (last screening on 15 November 2013)

Requiring confirmatory test

(b/a) (c/b) A1 d (d/c) A2 e (e/c) B f (f/c) C g (g/c)

TargetPopulation

Participants Test results

Screenedoutside

Fukushima

ClassA

Proportion (%) Proportion (%)

A1 decreases with age and A2 increases with age. A2 reaches a peak and decreases after that at the age of 13 to 15. B increases with age after adolescence. As for sex difference, A2 and B are predominance to the woman after adolescence.

Result of first screening classified by sex and age

( )単位人

０～５歳 27,103 24,911 52,014 10,411 10,754 21,165 31 44 75 0 0 0 37,545 35,709 73,254

６～１０歳 18,753 16,158 34,911 21,212 21,577 42,789 95 177 272 0 0 0 40,060 37,912 77,972

１１～１５歳 17,705 15,156 32,861 19,012 20,744 39,756 257 514 771 0 0 0 36,974 36,414 73,388

１６歳～ 7,402 7,617 15,019 6,324 7,645 13,969 231 446 677 0 1 1 13,957 15,709 29,666

合計 70,963 63,842 134,805 56,959 60,720 117,679 614 1,181 1,795 0 1 1 128,536 125,744 254,280

0 0

0 0

A1, 72.2%

A1, 46.8%

A1, 47.9%

A1, 53.0%

A2, 27.7%

A2, 53.0%

A2, 51.4%

A2, 45.3%

B, 0.1%

B, 0.2%

B, 0.7%

B, 1.7%

0% 20% 40% 60% 80% 100%

０～５歳

６～１０歳

１１～１５歳

１６歳～

A1

A2

B

C

A1, 69.8%

A1, 42.6%

A1, 41.6%

A1, 48.5%

A2, 30.1%

A2, 56.9%

A2, 57.0%

A2, 48.7%

B, 0.1%

B, 0.5%

B, 1.4%

B, 2.8%

0% 20% 40% 60% 80% 100%

０～５歳

６～１０歳

１１～１５歳

１６歳～

A1

A2

B

C

年齢階層別判定区分の分布【男性】年齢階層別判定区分の分布【女性】

Ages 0-5 23,639 21,729 45,368 8,095 8,476 16,571 27 35 62 0 0 0 31,761 30,240 62,001

Ages 6-10 17,393 15,027 32,420 18,914 19,268 38,182 85 159 244 0 0 0 36,392 34,454 70,846

Ages 11-15 16,195 13,874 30,069 16,910 18,442 35,352 226 441 667 0 0 0 33,331 32,757 66,088

Ages 16-18 6,787 6,881 13,668 5,595 6,753 12,348 198 387 585 0 1 1 12,580 14,022 26,602

Total 64,014 57,511 121,525 49,514 52,939 102,453 536 1,022 1,558 0 1 1 114,064 111,473 225,537

0 0

0 0

A1, 74.4%

A1, 47.8%

A1, 48.6%

A1, 54.0%

A2, 25.5%

A2, 52.0%

A2, 50.7%

A2, 44.5%

B, 0.1%

B, 0.2%

B, 0.7%

B, 1.6%

0% 20% 40% 60% 80% 100%

Ages 0-5

Ages 6-10

Ages 11-15

Ages 16-18

A1

A2

B

C

A1, 71.9%

A1, 43.6%

A1, 42.4%

A1, 49.1%

A2, 28.0%

A2, 55.9%

A2, 56.3%

A2, 48.2%

B, 0.1%

B, 0.5%

B, 1.3%

B, 2.8%

0% 20% 40% 60% 80% 100%

Ages 0-5

Ages 6-10

Ages 11-15

Ages 16-18

A1

A2

B

C

Test results by age group (Male) Test results by age group (Female)

Ages 0-5 23,639 21,729 45,368 8,095 8,476 16,571 27 35 62 0 0 0 31,761 30,240 62,001

Ages 6-10 17,393 15,027 32,420 18,914 19,268 38,182 85 159 244 0 0 0 36,392 34,454 70,846

Ages 11-15 16,195 13,874 30,069 16,910 18,442 35,352 226 441 667 0 0 0 33,331 32,757 66,088

Ages 16-18 6,787 6,881 13,668 5,595 6,753 12,348 198 387 585 0 1 1 12,580 14,022 26,602

Total 64,014 57,511 121,525 49,514 52,939 102,453 536 1,022 1,558 0 1 1 114,064 111,473 225,537

0 0

0 0

A1, 74.4%

A1, 47.8%

A1, 48.6%

A1, 54.0%

A2, 25.5%

A2, 52.0%

A2, 50.7%

A2, 44.5%

B, 0.1%

B, 0.2%

B, 0.7%

B, 1.6%

0% 20% 40% 60% 80% 100%

Ages 0-5

Ages 6-10

Ages 11-15

Ages 16-18

A1

A2

B

C

A1, 71.9%

A1, 43.6%

A1, 42.4%

A1, 49.1%

A2, 28.0%

A2, 55.9%

A2, 56.3%

A2, 48.2%

B, 0.1%

B, 0.5%

B, 1.3%

B, 2.8%

0% 20% 40% 60% 80% 100%

Ages 0-5

Ages 6-10

Ages 11-15

Ages 16-18

A1

A2

B

C

Test results by age group (Male) Test results by age group (Female)


Male Female

Thyroid ultrasound findings in children from three Japanese prefectures: Aomori, Yamanashi and Nagasaki

Aomori

Fukushima

YamanashiNagasaki

A1; 134805; 53.0%

A2; 117679; 46.3%

B; 1795; 0.7% C; 1; 0.0%

A1A2BC

Result of Fukushima

A1; 1853; 42.5%A2; 2468; 56.5%

B; 44; 1.0%

A1A2BC

Results of three prefecturesN=4,365

N=254,280Radiation Medical Science Center for the FHM survey, FMU

To obtain such comparative data, the Japan Association of Breast and Thyroid Sonology (JABTS) was entrusted from the Ministry of Environment using by the same method as Fukushima Thyroid Ultrasound Examination (TUE).

* **

Confirmatory testing coverage and results as of 31 December 2013

a b c (c/b) d (d/c) e (e/c) f (f/c) g (g/f)

369 ( 42.4)83 ( 6.2) 388 (28.9) 871 (64.9)Total 1,796 1,490 (83.0) 1,342 ( 90.1)

FY 2013 591 426 (72.1) 329 ( 77.2) 21 ( 6.4)

50 ( 6.1)FY 2012 987

130 (39.5) 178 (54.1) 37 ( 20.8)

243 ( 43.5)217 (26.3) 559 (67.7)872 (88.3) 826 ( 94.7)

(21.9) 134 (71.7) 89 ( 66.4)FY 2011 218 192 (88.1) 187 ( 97.4) 12 ( 6.4) 41

Number ofchildrenrequiring

confirmatorytest

Participants Confirmed test results

Next screening advised Follow-up advised

A1 A2Cytology

(b/a)

Proportion (%) Confirmatory testcoverage (%)

Results of Secondary Examination (Confirmatory Examination)

started from March 2012 to December 2013

*: One-third cases recommended next full scale survey from April 2014 since it was re-judged by A1 and A2 without abnormal findings. **: The cases are going to shift to the usual medical examination and to re-consult in six months or one year in general. ***: The FNAC in 369 cases revealed that 75subjects had a malignant tumor or were suspected to have malignancy.

Among 871 cases excluding A1 , A2 re-judged cases, 369 (42%) cases were diagnosed by FNAC after ultrasound examination and 502 (58%) cases were diagnosed by ultrasound examination alone.


Proportion of suspicious or malignant cases 0.03%

Malignant or suspected malignant cases diagnosed by FNAC

Preliminary surveys from Oct. 2011 to December 2013


Age and gender of 75 cases, who were diagnosed with malignant or suspected malignant by FNAC

pregnancy

<1 1 2 3 4 5 6 7 8 90

2

4

6

8

10

12

14

FemaleMale

Years

Nun

ber o

f Cas

es

There was no youngest children of thyroid cancer in Fukushima unlike as Chernobyl children after the accident .

Nikiforov 　 Y, et al. Pediatric Thyroid Cancer after the Chernobyl Disaster. Cancer 1994; 74:748-66

Figure 3. Age and sex distributions of patients at the time of the Chernobyl accident.

Suspicious or malignant cases by age as of 11 March 2011

Suspicious or malignant cases by age as of the date of confirmatory examination

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

女性男性

(人)

(歳)

FemaleMale

Number

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

女性男性

(人)

(歳)

FemaleMale

Number


Suspicious or malignant cases on FNAC by estimated radiation dose

Thirty-one of the 75 cases (41.3%) participated in the Basic Survey (radiation dose estimates), and 24 cases were confirmed, of which 12 (57.1%) had estimated radiation exposure dose below 1 mSv.


Number of suspicious or malignant cases by age and dose

0-5 6-10 11-15 16-18 TotalMale 0 0 0 1 1

Female 0 1 1 3 5Male 0 0 3 1 4

Female 0 1 0 4 5Male 0 0 2 1 3

Female 0 0 3 1 4Male 0 0 1 0 1

Female 0 0 1 0 1Male 0 0 6 3 9

Female 0 2 5 8 15Total

SexAge at the time of disasterEffective

dose(mSv)

<0.5

<1.0

<1.5

<2.0

０−１５１６−１９９

２００−３９９

４００−５９９

６００−７９９

８００−９９９

１０００−１２

４９１５０

０−１９９９

２０００−２９

９９３００

０＋0

100

200

300

400

500

600

700

154

579

240172

12193 74

32 33 38

０−１５１６−１９９

２００−３９９

４００−５９９

６００−７９９

８００−９９９

１０００−１２

４９１５０

０−１９９９

２０００−２９

９９３００

０＋0

200

400

600

800

1000

1200

1054

26

Comparison of Thyroid Equivalent Dose between Chernobyl and Fukushima’s children after the either accident

Thyroid Equivalent Doses (mSv)

No

No

Chernobyl(N=1576)

Fukushima(N=1080)

Cardis E., et al. JNCI 97:274,2005

http://www.nsr.go.jp/archive/nsc/anzen/shidai/genan2011/genan031/siryo4-3.pdf

Did thyroid cancer occur in these patients as a result of radiation exposure after the Fukushima Daiichi Nuclear Power Plant Accident ？

1. The exposure level in Fukushima was overwhelmingly low. It is likely that there are no children who have exceeded the maximum exposure level of 50mSv (intervention level) .

2. Radiation induced thyroid cancer will show the symptoms following an incubation period of at least four to five years, however it is still a little less than three years during the period after the accident.

3. The carcinogenic risk would be heightened if the ages of the cases were young at the time of the accident, but the average age of these malignant or suspected malignant cases was 15 years old, and younger children is not accepted .

4. All cases were diagnosed with typical PTC, and there were no solid variant PTCs like in Chernobyl’s PTC.

• As mentioned above, a possibility that a thyroid cancer which was accepted by the adult by having performed the highly precise medical examination until now was discovered at an early stage or youth while it was small is high.

• It seems that it had already occurred regardless of radiation exposure. • This serves as frequency of the thyroid cancer of the baseline of the children of

Fukushima.

The answer is no. Because,


Conclusion• This long-term large scale thyroid ultrasound examination (TUE) was

started.• At present, TUE of preliminary survey has been performed on about

270,000 children.• Among 369 cases where FNAC was performed in confirmatory test of

the Preliminary Survey, 75 cases were diagnosed with malignancy or suspected for malignancy, and 34 of these cases were already confirmed as having one benign nodule and 33 thyroid cancers after thyroid surgery.

• This is the interim report of the thyroid examination of the Fukushima Health Management Survey after the Fukushima Daiichi NPP accident, which potentially serves as baseline frequency of the childhood thyroid nodules/cysts in Fukushima discovered by newly introduction of the sophisticated ultrasound screening.

• These results will become the golden standard of the future comparative TUE in Fukushima, Japan whether the risk of childhood thyroid cancer will increase or not in future on a basis of well designed epidemiological study.

Thank you for your attentionRadiation Medical Science Center for the FHM survey, FMU

Documents

FMU Thyroid Ultrasound Surveys in Fukushima Prefecture