Fukushima Thyroid Examination February 2020: 186 Surgically Confirmed as Thyroid Cancer Among 237 Cytology Suspected Cases


Highlights 
  • The third round: 1 case newly diagnosed as suspicious or malignant, and 5 new cases surgically confirmed. 
  • The fourth round: 3 cases newly diagnosed as suspicious or malignant, and 7 new surgical cases. 
  • Age 25 Milestone Screening: 2 cases newly diagnosed as suspicious or malignant, no new surgical case. Age and tumor diameter data revealed for the first time.
  • Total number of suspected/confirmed thyroid cancer is now 236 excluding a single case of benign tumor: 115 in the first round, 71 in the second round, 30 in the third round, 16 in the fourth round, and 4 in Age 25 Milestone Screening.
  • Total number of surgically confirmed thyroid cancer cases has increased by 12 to 186 (101 in the first round, 52 in the second round,24 in the third round, 8 in the fourth round, and 1 in Age 25 Milestone Screening).
  • This session reported data as of September 30, 2019. September data is usually released in late December, but for some unclear reason the December session was never held in 2019. 
  • No official English translation of the results have been released since the December 2018 meeting. It is unclear if it will ever resume. The materials page on the new website has a list of previous translations, downloadable as one file per session. The old website shows individual reports for each session.

The latest overall results including "unreported" cases
(See this post for description of the "unreported" cases. Histological diagnosis of the 11 unreported cancer cases obtained from this paper.)


Overview
     On February 13, 2020, the 37th session of the Oversight Committee for the Fukushima Health Management Survey (FHMS) convened in Fukushima City, Fukushima Prefecture. It has been 4 months since the last session on October 7, 2019, skipping a regularly scheduled December session for an unknown reason. It seems that Fukushima Prefecture might be moving towards holding 3 sessions a year rather than quarterly sessions.

    The latest results of the third and fourth rounds of the Thyroid Ultrasound Examination (TUE) (as of September 30, 2019) were released as well as the results of the Age 25 Milestone Screening to be reported every 6 months. 
    Official English translation, ordinarily available on the website of Office for International Cooperation at the Radiation Medical Science Center for the Fukushima Health Management Survey, has not been released since the 33rd session on December 27, 2018. According to the most recent entry in Announcements, this translation was posted online on April 5, 2019, over 3 months after the 33rd session was held. It doesn't seem like Fukushima Medical University (FMU) is keen on providing translations. If it resumes, it's probably going to be posted on the new Radiation Medical Science Center website (link).
Summary on the current status of the TUE
     A six-page summary of the first through fourth rounds as well as the Age 25 Milestone Screening, "The Status of the Thyroid Ultrasound Examination," lists key findings from the primary and confirmatory examinations as well as the surgical information. This summary is not translated into English officially, but here's an unofficial translation which hopefully helps make up for the unavailability of the entire results in English. 



The third round
   The third-round results between April 1, 2019 and June 30, 2019 show that the primary examination participation rate remained at 64.7% with an additional 25 undergoing the examination. Two more participants, assessed "B," became eligible for the confirmatory examination. These numbers are small but the examinations are still ongoing and the results are not finalized just yet.
   Eight participants underwent the confirmatory examination and two underwent FNAC.  One person, a female from Hamadori was diagnosed with suspected thyroid cancer. She was age 9 at exposure. Her second-round result was A2 nodule. This makes "30" the total number of suspected thyroid cancer cases in the third round.
   There was five new surgical cases from the third round, with the total of 24 surgically confirmed thyroid cancer cases, all papillary thyroid cancer. 

The fourth round
   The fourth round, scheduled from April 1, 2018 through March 31, 2020, is actively ongoing. The current participation rate for the primary examination is 46.5%, up from the previous 40.1% but still lower than the prior rounds (81.7% for the first round, 71.0% for the second round, and 64.7% for the third round).
  Ninety-two participants newly underwent the confirmatory examination with a participation rate to 59.8%. Six participants newly underwent FNAC, and 3 of them were diagnosed with suspected thyroid cancer, making "16" the total number of suspected thyroid cancer cases in the fourth round.
   The 3 suspected thyroid cancer cases are all from Nakadori, consisting of 2 males (ages-at-exposure 10, 10) and 1 female (age-at-exposure 7). Their third-round results were one case with A1 and two cases with A2 cyst.
   There was one new surgical case for the fourth round, with the total of 8 surgically confirmed thyroid cancer cases, all papillary thyroid cancer.

Age 25 Milestone Screening
   The participation rate for Age 25 Milestone Screening remains low at 9.6%, although it's up by 2.5%. Sixty-two participants newly underwent the confirmatory examination with a participation rate of 73.2%. Four more underwent FNAC and two (1 male and 1 female) were diagnosed with suspected thyroid cancer.
    This is the first time details of the FNAC results such as average age and tumor diameter were released. There is no additional surgical case this time, leaving one surgically confirmed thyroid cancer case (papillary thyroid cancer) for this group.

Results from the previous screening 
     Below is information on previous assessments of the suspected/confirmed thyroid cancer cases. In the second round, 33 of 71 cases were assessed as "A1" meaning there were no ultrasound findings. Thirty-two were assessed as "A2" with ultrasound findings of nodules ≤ 5.0 mm and/or cysts ≤ 20.0 mm, 5 were assessed as "B" with nodules  5.1 mm and/or cysts  20.1 mm. Of 32 cases with A2, 25 cases had cysts. Having previous assessments of "A1" or "A2 cysts" means there was no precancerous lesion during the prior TUE, i.e., cancer supposedly appeared since the prior TUE. (Note: FMU claims the cancerous lesions were simply "invisible" during the prior TUE.)
  • 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 (30 cases):  6 cases with A1, 14 cases with A2 (4 nodules and 10 cysts), 7  cases with B, 3 cases previously unexamined
  • Fourth round (16 cases): 3 cases with A1, 10 cases with A2 (2 nodules and 8 cysts), 3 cases with B
  • Age 25 Milestone Screening (4 cases): 1 case with A2, 3 cases previously unexamined

No comments:

Fukushima Thyroid Examination February 2020: 186 Surgically Confirmed as Thyroid Cancer Among 237 Cytology Suspected Cases

Highlights   The third round: 1 case newly diagnosed as suspicious or malignant, and 5 new cases surgically confirmed.  The fourth ...