【Thyroid Cancer in Fukushima】How the Thyroid Examination Should Be: “Respecting a Wish Not to Participate in the Examination”

On June 15, 2016, Fukushima Minyu, one of the major regional newspapers in Fukushima Prefecture, published an article featuring Sanae Midorikawa, M.D., Ph.D., an endocrinologist who has been making school visits in Fukushima Prefecture to educate children regarding the thyroid examination they participate in. Midorikawa is also an associate professor in the Radiation Health Management at Fukushima Medical University and tasked with communication with residents. (Note: the article has been deleted from the Fukushima Minyu website. See the archived version).

The article (archived here) describes how Midorikawa is "accommodating" wishes of those children who do not want to participate in the thyroid examination that might lead to "unreasonable diagnosis of thyroid cancer." The "unreasonableness" is apparently based on the opinion of Fukushima Medical University that the thyroid cancer cases found during the first 4 years after the Fukushima Daiichi nuclear power plant accident are not due to radiation effects but simply a result of mass screening. In other words, these diagnoses are considered "unreasonable" because these cancers might never have been found until later in life without the mass screening.

It is true that cancer diagnosis can cause mental anguish and stress. When it happens to children, it is even worse since children usually do not get cancer. However, it also seems unreasonable that Fukushima Medical University is prematurely declaring "no radiation effects" for thyroid cancer cases in Fukushima children only based on the results of the first round screening. In fact, the second round screening—just completed but some results still pending—is showing more cases of thyroid cancer than explainable by "screening effect" which should not even be an issue during the second round. (See this post for the latest results.)

Although it is important to address the anxiety and fear felt by children (and their loved ones) who participate in the examination, they and their families also deserve to receive unbiased, realistic information regarding radiation risks. Yes, their exposure doses might not be as high as the Chernobyl population, but there are many uncertainties about the actual exposure doses in Fukushima. It is inferred in the recent paper by Fukushima Medical University published in Thyroid that radiation-induced thyroid cancer is not likely to appear in Fukushima because the exposure doses do not exceed 100 mSv, but this so-called 100 mSv threshold discourse has been scientifically disproven by recent studies such as the Australian CT study and the Swiss background radiation study.

The unofficial English translation of the Fukushima Minyu article  (archived here) is presented below in an attempt to share with the international community the view of a Fukushima Medical University researcher. (Addendum: FMU released an official English translation here.)

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Milepost Towards Reconstruction: Five Years of History
How the Thyroid Examination Should Be: “Respecting a Wish Not to Participate in the Examination”

“Should we leave alone the unreasonableness of being diagnosed with cancer in rare occasions after participating in an examination with unclear purposes?” 

   Beginning the last fiscal year, Sanae Midorikawa (age 48), an associate professor in the Department of Radiation Health Management at Fukushima Medical University who is in charge of communication regarding the thyroid examination, started the “demae jugyou” (translated to “delivered class” in English) geared towards children. It is because she felt it was unreasonable for many children to participate in the examination without knowing the purpose of the examination: watching over health.

   The thyroid examination targets Fukushima residents who were 18 or younger at the time of the nuclear accident. Cases of thyroid cancer have been detected among the participants, but the Fukushima Health Management Survey Oversight Committee, comprising physicians and experts, has consistently expressed an opinion that, “At the present time, they are unlikely to be due to the effect of radiation.” A possibility has been pointed out that a sensitive mass screening has detected many cases of cancer which were not previously found.

   Against the backdrop of parental concern, most children in Fukushima underwent the examination. However, Midorikawa thinks, “It is important to offer options to participate or not participate in the examination, after parents and children reach the understanding about the meaning and limitations of the examination.”

   In general, most cases of thyroid cancer are curable, and it is unlikely that thyroid  screening will lead to the merit of “reduced mortality. On the other hand, thyroid screening is not globally recommended due to the demerit of mental effects of being diagnosed with cancer. “Considering these merits and demerits, we have reached a point in time, now that five years have passed, when we need to consider how the thyroid examination should be.”

   At the delivered classes, Midorikawa explains to children about the possibility of the examination detecting cancer and tells them, “For those of you who ‘don’t want cancer diagnosis,’ your wish not to participate in the examination will be respected.” 

   In the past five years, anxiety about radiation amongst Fukushima residents took precedence over addressing the need by children to agree to participate in the examination or securing sufficient understanding of the demerits of the examination. Midorikawa reflects back, “It is not surprising that residents thought, ‘Our children should participate in the examination” after the nuclear accident. It also makes sense they connected the results with radiation and felt anxious. However, looking back, all of that was an irrational experience.”

   Unreasonableness experienced by parents and children in Fukushima Prefecture is not limited to the thyroid examination. Immediately after the accident, Chiharu Itoh (age 44), the vice principal of Fukushima Mebae Kindergarten (Fukushima City), established a one-on-one counseling room to address concerns of the mothers, dealing with various worries such as, “Should we evacuate outside Fukushima?” and “Should we avoid Fukushima products?”

   Now that five years have passed, some are beginning to voice positive opinions about the experience. “Mothers are interested in applying their experiences in adverse circumstances to the rest of their lives.” 

   Coming in contact with children during the delivered classes, Midorikawa hopes, “In the future, they will have to make important decisions regarding health risks other than radiation. It is my hope that, at such times, they will take their experiences in the past 5 years as helpful information in making a decision.