Toru Takano　Rinku General Medical Center, Japan

In October 2024, “Overdiagnosis of Thyroid Cancer in Fukushima” (AkebiShobo), which I co-authored with domestic and international experts, was published. This book describes the detailed trends of those involved in the overdiagnosis of thyroid cancer in Fukushima. Overseas experts who read this book will realize that Japan’s medical system, which is generally highly regarded internationally, actually contains serious problems.

When the Fukushima Daiichi nuclear accident occurred in 2011, countermeasures were implemented based on the experience of the Chornobyl nuclear accident. As a result, residents’ exposure to radiation was successfully reduced. The risk of thyroid cancer, which had been a concern, was prevented. However, following the example of Chornobyl, thyroid ultrasound (US) screening was carried out on an even larger scale, which led to overdiagnosis, uncovering small thyroid cancers that would otherwise have gone unnoticed throughout their lives. As a result, hundreds of children in Fukushima underwent surgery for thyroid cancer. This is an ironic result, considering that the original purpose of the radiation exposure countermeasures was to prevent such surgery.

It was discovered in 2014, three years after the start of the Fukushima thyroid examination, that it was causing health damage due to overdiagnosis. Now that reports have been issued by international expert organizations such as the United Nations UNSCEAR, WHO (IARC), and SHAMISEN, it can be said that this is an international consensus.

There have been two opportunities to modify the examination. The first was when Drs. Shoichiro Tsugane and Kenji Shibuya pointed out the possibility of overdiagnosis at the expert committee in Fukushima in 2014, and the second was when Dr. Sobue Tomotaka and I submitted a proposal to change the examination to Fukushima Prefecture in 2018. In both cases, Fukushima Prefecture avoided discussing the problems with the examination, and as a result, its method was not reviewed. Currently, the number of children and young people who may have been victims of overdiagnosis is estimated to be around 400, including cases found outside of the screening process, but, regrettably, the number would have remained at around100 and 200 if the method had been reviewed in 2014 and 2018, respectively. Above all, the damage in Fukushima continues to grow even now.

The biggest problem with the examination method is that thyroid US examinations that could be harmful to children’s health are conducted during school hours. This essentially forced children to undergo the examination, which maintained a high participation rate and led to an increase in the number of victims. Furthermore, the fact that a huge budget was allocated and a huge amount of research data could be obtained from the examination has become a strong incentive for those involved to continue the examination. Conversely, if the school examination were to be stopped, this incentive would disappear, so voices calling for continuing the examination would weaken, and the problem would move toward a solution all at once.

As mentioned above, Dr. Sobue and I have pointed out the problem with the school examination and submitted a proposal to the prefecture to stop it, and Senator Shun Otokita has also called for its suspension in the Diet. Despite these, Fukushima Prefecture has not reviewed the examination method. The 10 years since the problem was discovered and the issue has been left unattended is too long.

Before the nuclear accident, I wrote a paper stating that “thyroid cancer first occurs during childhood.” However, most experts in Japan at the time rejected my opinion. Therefore, it should have been unexpected that many small thyroid cancers were found in children as a result of the thyroid examination in Fukushima. Of course, predictions often can go wrong in the medical field, and no one can blame them for that. Initially, I believed that the people who started the examination would use their good sense to correct their views and lead the way in revising it. However, surprisingly, this did not happen. The reason I participated in the expert committee in Fukushima in 2017 was to revise the Fukushima thyroid examination to be in line with science. I believed that if I presented a scientifically correct view there and the other committee members understood it, the problem would move towards resolution. However, this did not happen here either.

The government still does not officially admit the existence of damage caused by overdiagnosis, and the related experts claim that “measures have been already taken to prevent overdiagnosis,” “the advantages and disadvantages of the thyroid examination have been explained to the residents, and the consent of the subjects has been obtained, so there is no problem with continuing the examination.”

Not only in Japan but also in other countries, when a mistake in a medical project occurs, those who promoted it often do not admit their fault and instead insist on their legitimacy. When excessive thyroid US examinations caused overdiagnosis in South Korea, the Korean Thyroid Association, which led the examinations, flatly denied the damage. However, at the same time in South Korea, conscientious experts spoke out and led the reduction of US examinations to contain the spread of damage. On the contrary in Fukushima, no such movement was seen. What is the difference?

The “turning a blind eye syndrome” is widespread in the medical community in Japan. When inappropriate medical procedures are being performed, it is the experts in the same field who should speak up first. They should take the initiative to express scientifically correct opinions and show the way to improve the situation. However, in Japan, everyone tries to avoid getting involved, even if they know that it would be a great help to the children of Fukushima who are in danger.

A typical example is the behavior of Japanese thyroid-related academic societies. Discussion of overdiagnosis is considered taboo in these societies. It is likely that the thyroid US screening in Chornobyl which began with the support of Japanese thyroid experts also caused the damage of overdiagnosis. However, even though 40 years have passed since then, they have not even been able to summarize it. In the journals of these societies, there are articles insisting on avoiding the discussion itself, saying “people who talk about overdiagnosis are a nuisance,” and there are even societies where the executives are actively spreading scientifically incorrect information such as “overdiagnosis and overtreatment have not occurred in Fukushima.”

Experts who are concerned about the current situation in Fukushima, including myself, have asked various people for cooperation. We sometimes receive heartwarming words of support, but in many cases, such requests for cooperation have been ignored. There are even some people who have become unreachable just by hearing the word “overdiagnosis” from us. As a result, even when unruly medical practices are being carried out, criticism is not made public, and no corrections are made. This situation will continue indefinitely until the people who started the mistake retire from the medical field.

This kind of thing has happened many times in the Japanese medical community. The story dates back 120 years to the Meiji era. Taro (Ogai) Mori, who was also a famous novelist, was the head military doctor of the army during the Russo-Japanese War of 1904. At that time, beriberi was a major problem in the military. The navy had succeeded in eradicating beriberi by changing the diet from rice, which does not contain vitamins, to wheat, but even though he knew this information, Mori did not waver from his theory that beriberi was an infectious disease and ordered that soldiers be provided with rice, which resulted in the tragic deaths of 27,000 soldiers from beriberi. It is said that Mori never admitted to his mistake throughout his life. It was not until 1925, after Mori’s death, that the theory that beriberi was caused by a vitamin deficiency became established in Japan.

Next was the mass screening of newborns for neuroblastoma in the 1990s. This test was started by leading academics at the time with the backing of the government. However, it soon became clear that the test did not improve prognosis and instead caused harm through overdiagnosis. However, the experts who promoted the test were unable to admit their mistake, and those around them developed a “blind eye syndrome,” so no criticism was made within Japan. Although nationwide screening was eventually discontinued following criticism from overseas, the testing continued in some areas for as long as 30 years.

This was also the case when the cervical cancer vaccine problem occurred. At that time too, the government’s decision to suspend vaccination recommendations should have been met with active discussion among relevant experts, who should have disseminated information and considered resuming vaccination. However, many people were hesitant to take on the issue, and as a result, the issue was left unattended for years, which drew international criticism. And now we are faced with the current Fukushima problem. How many times will Japan’s medical community repeat the same mistake?

The issue of overdiagnosis of thyroid cancer in Fukushima is a typical example of the “turning a blind eye syndrome.” If the current situation is left unchecked, similar cases will occur frequently in the future, which may even lead to the collapse of the medical system. Those who lead the medical system in Japan are unable to correct their mistakes even when they make incorrect decisions. In addition, even when inappropriate medical procedures are being performed, no medical professionals reach out to help those in need. Would people want to entrust themselves or their families to such medical professionals? In this way, medical professionals will lose the trust of the general public, and the good old days when a medical doctor was considered a sacred job will never come again.

Furthermore, there is the issue of the Declaration of Helsinki in the case of the thyroid examination in Fukushima. In Fukushima and Chornobyl, Japanese researchers have supported thyroid US screening of children and young people, and published research papers using the data obtained. Thyroid US screening has no clear benefits and instead causes health damage to subjects due to overdiagnosis. Such research may violate the Declaration of Helsinki, which sets out ethical standards for medical research, stating that “research that harms subjects should not be conducted.” The Declaration of Helsinki was created as a reflection on the human experiments conducted by Nazi Germany. In Japan, such research is being conducted with a disregard for international ethical standards, and it is the university ethics committees that give the green light. If this situation is allowed to continue, people overseas will think that Japanese medical researchers do not hesitate to violate children’s human rights to obtain data, which will be a major hindrance to the promotion of future medical research in Japan.

As an expert, I would like to convey this message to the people of Fukushima Prefecture. Children should not be allowed to undergo the thyroid examination without knowing the meaning of “overdiagnosis.” There is a certain probability that the examination will cause lifelong physical and psychological scars on children. It should also be known that while Fukushima Prefecture never uses the word “overdiagnosis” in the explanation of the thyroid examination, it repeatedly announces that “the harms of the examination have been fully explained, and the examination is conducted with the consent of the subjects.” This means that even if subjects complain of health damage caused by the examination, there is a high possibility that they will be dismissed with “it can’t be helped, since you requested the examination.” as long as consent has been given in writing.

I would like to ask those experts who remain silent despite being aware of the risk of the thyroid examination in Fukushima. Will you continue to turn a blind eye? Fukushima will be recorded in history as the place where a nuclear accident occurred, but are you also going to leave a mark in medical history as the place where inappropriate medical treatment was administered? Is it acceptable for Japan to be a country that cannot save children who are in danger?

In the next five years, the youngest target age group will graduate from high school, and so the Fukushima thyroid examination program in schools will be completed. It is a great disgrace to the Japanese medical community if the school screening program, which is being carried out in a manner not in line with science and medical ethics, is completed as originally planned. There is not much time left for us to correct our mistakes.