投稿者: tamihei

Criticism of the 15th Prefectural Oversight Committee Meeting for Fukushima Health Management Survey

July 10, 2014

Yukihiko Fuse

The 15th Prefectural Oversight Committee Meeting for Fukushima Health Management Survey was held on May 19, 2014. The committee released the results of the Thyroid Ultrasound Examination including Aizu district (refer to the following table). One thing that became evident in this announcement is that there are regional disparities for the incidence of childhood thyroid cancer.

The radioactivity measurements were carried out in Fukushima City, Koriyama City, Shirakawa City, Aizu-Wakamatsu City, Minami-Aizu City, Minami-Soma City and Iwaki City from March 11 to March 31, 2011. The measurements were, needless to say, not for radioactive iodine but for radioactive cesium, but the situation of the radioactive iodine that had been spread at the time of the nuclear plant explosion shall be deemed similar to the leaked radioactive cesium. Therefore I use the figures as a substitute for iodine.

The results are as follows:

In Minami-Soma, the maximum record was 20μSv/h on March 12 and then hovered at between 2 and 4μSv/h until it dropped to below 1μSv/h on March 31.

In Iwaki City, the maximum record was 22.72μSv/h on March 15 and then hovered at between 1 and 3μSv/h until it dropped to below 1μSv/h from March 29. (The record passingly increased again to 18μSv/h on March 16 and 6μSv/h on March 21.)

In Fukushima City, the maximum record was 24.24μSv/h on March 15 and then gradually decreased but still continued to keep high level of 2.94μSv/h even on March 31.

In Koriyama City, the maximum record was 24μSv/h on March 15 and then gradually decreased but still continued to keep high level of 2.6μSv/h even on March 31.

Shirakawa City was the only one that conducted the measurement from the very day of March 11. On March 11, the figure of the measurement was 0.05μSv/h but it became to the maximum record of 7.70μSv/h on March 15 and then gradually decreased to below 1μSv/h on March 27.

In Aizu-Wakamatsu City, the maximum record was 2.57μSv/h on March 15 but decreased to below 0.6μSv/h on March 17.

In Minami-Aizu City, the maximum record was 1.08μSv/h on March 15 but decreased to below 0.3μSv/h on March 16.

The above results turn out to be the following facts;

1.Minami-Soma City was affected by the Fukushima Unit 1 Explosion on March 12 and other cities were affected by the Fukushima Unit 2, 3 and 4 Explosion on March 14 and 15.

2. Fukushima City and Koriyama City were exposed to high level of radiation compared to other districts and it lasted for a prolonged period.
3. While on the other hand, Aizu district has been little-affected by radiation.

Looking at the incidence of childhood thyroid cancer by districts, the radiation dose closely correlates with the incidence. The Aizu district was exposed to the low radiation dose compared to other districts and only 1 child of Shimogomachi developed childhood thyroid cancer. The   incidence of Aizu district is 1 to 32,208 children. But in Fukushima City where the radiation dose was very high, the incidence in Nakadori is 1 to 2,898 children (about 11 times higher than Aizu district) and in Hamadori, 1 to 3,577 children (about 9 times higher than Aizu district).

7th Session of Expert Meeting Discussing Health Suport

On June 26, 2014, “7th Session of The Ministry of the Environment Expert Meeting Discussing Health Support After the Fukushima Nuclear Accident” took place and the Specially Appointed Professor to Director of Fukushima Medical University, Otsura Tanba, stated as follows;

“I have been studying biology of radiation accidents for quite a long time. As I have been carrying out merely experimental carcinogenesis and cellular analysis in mouse, I have very limited knowledge of radiation protection. But referring to the  incidence, I can say that there would be no development of cancer in a place with a low radiation dose. It is a hard fact. Cancer may develop stochastically, but I think that there is no development of cancer in a place with an immeasurably low radiation dose. It is just the same in Hiroshima and Nagasaki.”

There are very few cases of childhood thyroid cancer in Aizu district because the radiation dose was very low.

Defective design of ultrasound examination

The second problem is that although the survey is claimed to be a “prefecture-wide inventory survey,” the subjects of the thyroid ultrasound test are only around 80% of the target population, because of flawed design of the Fukushima Prefecture government’s ultrasound examination. The examined were the only people who were able to go to the designated school buildings or gyms on designated dates and time where the ultrasound examination were conducted by some very limited medical institutions—the Fukushima Medical University and some major hospitals; around 20% of the target population could not get the examination at the fixed time and place.

In order to improve this defective survey design, it is indispensable to let all the medical institutions in Fukushima participate in the survey and to make it easy for all the target population to receive ultrasound examination at their neighboring institutions. In Belarus, the exposed to radiation have been still receiving ultrasound examination once in six months since the Chernobyl disaster 28 years ago. Not just children, but adults must be examined. Long-time observation is needed through their entire lives.

It is impossible for the FMU and some major institutions in Fukushima alone to deal with such challenges. Comprehensive initiative with participation and support of the entire medical institutions in Fukushima is definitely needed.  Also the Judging Panel that has been conducted solely by the FMU must include various medical institutions.

 Lymph node metastases already found

At the session of the Thyroid Examination Evaluation Subcommittee on June 10, 2014, a member of the subcommittee, Kenji Shibuya, professor at the Tokyo University, raised a question: “Don’t you consider the 51 thyroid surgery over-diagnosis and over-treatment (if these cases are attributable to the ‘screening effect’, and the optimum approach to them is wait-and-see.)?”

“Only those who really need it are cytologically diagnosed,” the FMU professor Shinichi Suzuki replied. “The detection of malignancy or suspected malignancy in our cytodiagnosis … does not mean that we performed so-called over-diagnosis and over-treatment. As for cytodiagnosis (of a 5 to 10 mm nodule), we recommended such diagnosis for children who had strongly suspected malignancy. In the case of a 5 to 10 mm nodule, we resected it only when it was highly malignant. Then, lymph node metastasis was detected in almost all of such cases. We did not unnecessarily resorted to resection only because patient was a child. Metastasis was clinically clear. Patients with a hoarse voice must be treated.” He explained that the surgeries were conducted based on the clinical appearance.

Previously, Professor Suzuki had underscored thyroid cancer’s good prognosis and slow progression.  If it were the case, a wait-and-see policy without any surgery would suffice, as remarked by Professor Shibuya. Professor Suzuki, however, conducted aspiration biopsy cytology for 437 persons because it was really needed. There was urgent necessity of 51 surgeries because of lymph node metastasis and other pathological conditions.

Despite as many as 51 thyroid cancer surgeries, the Fukushima Prefecture and the central governments insist that there is no health effect of radiation but the screening effect resulted in this figure, citing child thyroid ultrasound examination in three prefectures—Aomori, Yamanashi and Nagasaki. They reported that the result of the three-prefecture examination has no significant difference compared with that of Fukushima because 4,365 subjects were examined by ultrasound in the three prefectures and 2,368 (56.5%) were judged as A2 and 44 as B, in which 31 who gave consent were further examined by aspiration biopsy cytology and 1 case of child thyroid cancer was detected.

In Fukushima, 1 child thyroid cancer case was found in around 5,700 subjects. If there is no significant difference in the incidence rates all around the country as stated by the Fukushima Prefecture and the central governments, they must face with 1 in 4,000 or 6,000 children in all over Japan to whom they have to give thyroid cancer surgery. In fact, it is well known in the field that the overall child cancer incidence in Japan is 1 in 10,000. Their assertion logically implies that there are far more child thyroid cancer patients who need surgery than all kinds of child cancer cases. If the government still insist that Fukushima’s figure is not the result of the radiation exposure, they must immediately conduct ultrasound examination of all children around Japan.