Statement of the Medical Panel on the Governmental Recognition of A-Bomb Diseases
October 14, 2004
BBoard of Directors, Japan Federation of Democratic Medical Institutions (MIN-IREN)
MIN-IREN Radiation Exposure Commission
MIN-IREN Medical Panel Supporting the Collective Lawsuits for A-Bomb Disease Recognition
MIN-IREN: Heiwa-to-Rodo Center 7F, 2-4-4 Yushima, Bunkyo-ku, Tokyo 113-8465, Japan
TEL: +(81)3-5842-6451 FAX: +(81)3-5842-6460
URL: http://www.min-iren.gr.jp E-mail:email@example.com
|On Publishing the English Version of the Statement of the Medical Panel
|Glossary of Technical Terms
|1. Objectives of the present statement
|2. Our viewpoint in submitting the present statement
|3. Gist of the Statement
|4. Points in dispute regarding A-bomb disease recognition based on the "probability of causation" that solely relies on the DS8
||The mechanical application of the "probability of causation" model to individual A-bomb sufferers to deny the correlation of radiation with their A-bomb disease constitutes a misuse of epidemiology
||The plaintiffs are those who were exposed at a distance, or who entered the zone after the explosion. However they were actually exposed to a considerable amount of radiation and sustained damage on their health that cannot be explained by DS86 dosimetry alone
||Questions and Problems regarding the Basic Documents of ABCC/Radiation Effects Research Foundation Seen from Doctors' Point of View
||Questionable process of establishment of DS86 and irrelevance of its use for the evaluation of radiation dose for official recognition of A-bomb disease sufferers
||Kodama Paper, which provided the basis for the "probability of causation", does not reflect the evolution of mortality and incidence rates of the last 10 years
||DS86: Irrationality from medical point of view of the decision to turn down applications based on the data provided by the Radiation Effects Research Foundation
||In screening A-bomb disease applications, emphasis should be put on the actual conditions under which the applicants were exposed to the bombing as well as their clinical picture. Their applications should not be turned down on the grounds of a low “probability of causation”
||(1) A-bomb victims are highly likely to develop not only a single kind of cancer but multiple cancers
||(2) Incidence of prostate cancer is possibly higher among A-bomb sufferers
||(3) Recent increase in the mortality and morbidity of diseases other than cancer
||(4) Radiation causality of benign thyroid gland disease
||(5) Radiation causality of chronic hepatitis and cirrhosis
||(6) Radiation effects on cataracts among A-bomb victims
||(7) Burn injury and post-traumatic disorders
||(8) On determination of the need for medical treatment of the diseases of the plaintiffs
|5. Our views on the clinical pictures of the A-bomb victims’ diseases to be officially recognized
||Need for transformation of the administration of the recognition system based on the real suffering of the victims
||Solid cancers and malignant tumors should be recognized as A-bomb induced unless there is a clear alternative cause
||The current list of illnesses designated as A-bomb induced should be made more inclusive
||Appropriate requirements for the recognition of A-bomb illness
|List of Citations and References
On Publishing the English Version of the Statement of the Medical Panel
Dr. Kikima Hajime
Chair, MIN-IREN Radiation Exposure Commission
Japan Federation of Democratic Medical Institutions (MIN-IREN)
The first-ever nuclear holocaust created by the atomic bombing of Hiroshima and Nagasaki killed 210,000 people by the end of 1945. Of some 400,000 survivors (Hibakusha), the number has continued to decline over the years, with now about 266,000 victims remaining. Their average age has now reached the mid-70s.
For the last 60 years, the mental trauma of the Hibakusha who had witnessed the hell on earth has never healed; their physical health has also continued to be threatened by the various after-effects of the A-bomb radiation, including cancers.
The Hibakusha joined forces with the nationwide movement for a total ban on atomic and hydrogen bombs, triggered by the 1954 Bikini Hydrogen Bomb test disaster. The Hibakusha movement has pressed the government to establish an A-bomb disease recognition system and a number of official measures for the sake of the medical care and welfare of the Hibakusha, who have long been suffering from discrimination and illnesses.
However, the successive governments of Japan, blindly following the U.S. nuclear strategy, not only have turned their back on the desire of the Hibakusha for the abolition of nuclear weapons, but also turned their eyes away from the scientific truths on the health hazards caused by the A-bomb radiation. The government now even tries to limit the scope of and underestimate the damage caused.
Now, at 12 district courts all across Japan, a total of 168 A-bomb victims and their bereaved families have filed collective lawsuits against the government, seeking the reversal of their rejected applications for the recognition of A-bomb induced diseases. These court struggles are waged at the risk of their own life, aiming to fundamentally change the government’s Hibakusha policy, which underestimates the A-bomb damage.
This Statement of the Medical Panel was compiled in response to the request of Nihon Hidankyo (Japan Confederation of A-and H-Bomb Sufferers Organizations) and the Plaintiffs’ Councils of the collective lawsuits, with the view to realizing fair and scientific proceedings in the courts. Based on scientific and objective foundations, the Statement has demonstrated the possibility that a variety of illnesses have been caused as delayed effects of the A-bomb radiation.
In the course of the court proceedings, the defendants, i.e. the government, have tried to offer various counterarguments to this Statement, but so far they have been unable to present any reliable basis that can be scientifically verified.
During the three years since the collective lawsuits were filed, already 21 of the plaintiff Hibakusha have died as of December 2005. The days left for the Hibakusha are numbered. We earnestly hope that a fair and just judgment to allow the Hibakusha to feel peace of mind will be rendered as soon as possible.
With the support of the Board of Directors of Min-Iren, the Statement of the Medical panel has been translated into English. Now we can share the content with many people outside Japan concerned about the long-term health effects of the A-bomb radiation. This is not only a great honor for us doctors, but I believe that it will give great support to the A-bomb victims who have long struggled to abolish nuclear weapons at the cost of their lives.
Further, it is our sincere wish that this Statement will be of use to the people in understanding the health hazards inflicted on the victims of nuclear tests all over the world, and contribute to creating a world set free of nuclear weapons.
Last but not least, I express my sincere gratitude to the International Section staff of the Japan Council against A & H Bombs (Japan Gensuikyo), who took the trouble to translate the text in the midst of their preparation for the March 1 Bikini Day events.
Glossary of Technical Terms
Proximal Hibakusha: Hibakusha (A-bomb survivors) who were within 2 kilometers of the hypocenter at the time of the atomic bombing
Distal Hibakusha: Hibakusha who were further than 2 kilometers from the hypocenter at the time of the atomic bombing. Sometimes the term is more strictly defined as people between 2-4 kilometers of the hypocenter at the time of the atomic bombing.
Entrant Hibakusha: Hibakusha who were not near the hypocenter at the time of the bombing and were not therefore directly exposed to radiation from the explosion, but who entered the danger zone after the atomic bombing and were exposed to induced radiation and radioactive fallout.
Ionizing radiation: Radiation capable of ionizing molecules in cells. These ionizations can lead to cancer and other diseases.
Prompt radiation: Radiation released by the initial nuclear explosions (mostly gamma rays and neutrons).
Nuclear fission products: Atoms produced by the fission of uranium (Hiroshima bomb) and plutonium (Nagasaki bomb). The fission products were themselves radioactive and released radiation as they decayed.
Radioactive fallout: Radioactive materials contained in the mushroom cloud (e.g. nuclear fission products). This radioactive material was deposited over a wide area, particularly with rain (the so-called 'black rain').
Induced radiation: Neutrons produced by the nuclear explosions collided with other materials (for example air, or buildings) and some of these neutrons were absorbed by atoms in those materials. These atoms were thus turned into radioactive isotopes, which emitted radiation as they decayed.
Residual radiation: Radiation that was released after the initial explosion. It includes induced radiation and radiation from fission products.
Dose response: A dose response is a mathematical model that describes how a response variable--a biological measurement or epidemiologic population statistic--depends on the level of radiation dose. The dose-response model tells whether the level of response increases or decreases with dose and how rapidly it changes as a function of dose. (definition by RERF)
Kerma: Acronym for kinetic energy released in materials. Kerma is the sum of the initial kinetic energies of all the charged particles liberated by uncharged ionizing radiation (neutrons and photons) in a sample of matter, divided by the mass of the sample. Kerma is expressed in gray (or its submultiples), and, unless otherwise specified, refers to the energy liberated per unit mass in a small sample of tissue. Free-in-air kerma refers to the amount of radiation at a location before adjustment for any external shielding from structures or terrain. (definition by RERF)
1. Objectives of the present statement
As doctors, we sit face-to-face with A-bomb victims or Hibakusha in our consultation rooms and practice medicine day to day in pursuit of finding answers to the health and medical problems they face.
Being involved in the provision of treatment to A-bomb survivors on daily basis, we cannot but be strongly concerned about their ongoing collective litigation cases for A-bomb illness recognition.
This is because our long-standing doubts regarding the official A-bomb disease recognition policy are largely shared by Hibakusha themselves.
In sum, we question the so-called theory of "probability of causation" on which the Ministry's Guideline on the Recognition of A-bomb Illness* is built, the DS 86** that is considered as the basis for estimating the radiation exposure dose of each Hibakusha and the evaluation of various long-term studies on A-bomb victims carried on by the Radiation Effects Research Foundation (RERF).
In this jointly compiled Statement, we attempt to explain the background and the reasons of our doubts in the hope that this will be put to good use in the examination of A-bomb judicial cases being heard across the country.
*The Guideline on the Recognition of A-bomb Illness: This was approved in 2000 by the Subcommittee on A-bomb Victims Medical Issues of the Committee on the Recognition of Illness and Injury (Screening Committee).
**The dosimetry system approved in 1986 for estimating radiation doses to which victims of Hiroshima and Nagasaki atomic bombings were exposed.
2. Our viewpoint in submitting the present statement
In this country, once engaged in war, there are still many sufferers of war damage. Nothing distinguishes atomic bombing damage from ordinary war damage in that they both created a large number of victims. However, the sufferers of war damage could restore their health and hope for the future once their injuries were healed.
It was many years later that A-bomb sufferers came to know the hidden dimension of the atomic bombing: radiation effect. In fact, unlike the devastation of the heat rays and the blast of the bombs that they were able to see on the spot, radiation was invisible to them. It has never allowed them to have mental or physical peace for the past 59 years. It has left the survivors with indelible scars that will never heal.
We should not forget that A-bomb victims are those who were subjected to the use of nuclear weapons, an act prohibited both by international law and for humanitarian reasons. Thanks to the studies on delayed effects that have been carried on for almost 60 years, it is now widely acknowledged that the A-bomb radiation continues to affect the human body in many ways and for many years after acute symptoms have disappeared.
It is also well known that cancer and many other delayed radiation effects present no symptomatic or pathological characteristics that can be clearly distinguished from those caused by non-radiation factors, and therefore those radiogenic diseases show no apparent particularities. In addition, there is no simple way in day-to-day medical practice to evaluate the exposure dose of each individual Hibakusha.
However, Hibakusha who have managed to survive the last 59 years have actually suffered numerous fatal diseases and health disorders. The occurrence of these illnesses and disorders in Hibakusha had become uncontestable in medical practice even before the findings of RERF studies were made public.
We should also note that those who were exposed to the fierce blast and the heat rays continue to suffer from their effects. We should remember the case of a Nagasaki Hibakusha whose hemiplegia, caused by a head injury, was screened out from A-bomb illness recognition because of her distance from ground zero alone: at 2.45 kilometers she fell outside the "2-kilometer-criteria". She had to wage a court struggle for more than a decade before ultimately receiving judicial redress in the Supreme Court.
We earnestly hope that such Hibakusha cases will also be fairly judged by the courts in the light of the spirit of the foundation of the Relief Law, since the possibility of radiation exposure causing immunity disorders or delay in healing cannot be ruled out.
At this point, we realize that the "Guideline on Medical Treatment of Aftereffects of the Atomic Bombings" (hereafter referred to as “Treatment Guideline”) issued 13 years after the bombing has not lost its merits. It is a notice issued on August 13, 1958 by the Director of the Office of Public Health of the then Health and Welfare Ministry. We should like to quote and comment on important parts of the notice, since we believe that it gives relevant suggestions to the doctors who are treating Hibakusha and that it remains effective as a statute today.
First, the “Treatment Guideline” pointed, as a specific aspect of A-bomb delayed effects, to recognized distinct differences in the appearance and recovery process between external injuries caused by the atom bomb's heat rays and/or blast and ordinary injuries. It also pointed to the contribution of two different kinds of radiation to so-called radiation sickness: radiation immediately released by the explosion and radiation from radioactive material produced as a result of the nuclear explosion. (1)
"In the case of victims of the atomic bombings, the possibility of a connection with the atomic bombing should be considered for any illness or symptom. Special attention should be paid to the evolution of their illness or symptoms as well as to their prevention. Given that the delayed effects suffered by the victims are directly or indirectly connected with radiation produced by nuclear explosion, one can naturally expect that the radiation effects would vary among different individuals depending on the type of radiation to which they were exposed, in particular depending on the gamma and neutron doses. However, accurately assessing radiation doses is difficult in the first place. It is therefore necessary to consider the factors of each individual's illness and to make an assessment of the circumstances of each person's exposure at the time of the bombing. When providing medical care, two factors in particular need to be taken into consideration.
a) Distance from ground zero: It is considered that those who were within approximately 2 kilometers from ground zero at the time of the bombing received high doses of radiation; those at about 2 to 4 km from ground zero received moderate doses of radiation; and those at distances of 4 km or beyond received low doses of radiation. They therefore can be treated accordingly.
b) There are cases in which the extent of radiation effects on a victim can be assessed by identifying whether or not the victim suffered acute symptoms after the bombing and their severity, especially the symptoms, such as hair loss, high fever, and mucosal bleeding."
The medical basis of this Guideline is the studies undertaken by the US-Japan joint team established right after the bombing in September, 1945, under the aegis of the Manhattan Project research team and the results of numerous surveys done by Japanese researchers at medical schools and others who strived to do studies on and give aid to the survivors despite the constraints imposed by the occupation forces. The latter studies were later compiled into one book "Genshi Bakudan Higai Chosa Houkoku-shu (Collection of Studies on Damage of Atomic Bombings. Vol.1 & 2)" published in March, 1953 by the Japan Society for the Promotion of Science, a year after the peace treaty took effect.
Here, we want to insist on the fact that researchers at that time were interested in the acute symptoms and argued that radiation effects on the victims could also be assessed by observing the gravity of their symptoms. They also suggested that such effects should be taken into account even in cases where survivors were at places beyond 2 km from the hypocenter.
In addition, the indication that the healing process and appearance of external injuries caused by the atomic bombing were different from those of already known external or heat injuries bears an important meaning.
Seen from the viewpoint of treating A-bomb disease whose incidence cannot be denied even by present day medical knowledge, it is evident that the current screening method based on “probability of causation” is considerably cut off from the reality of the A-bomb destruction.
Also, unlike risk estimates for malignant tumors, in the case of late effects of thermal burns, external injuries, injuries from glass fragments etc., it is impossible to produce data on which to base a comparison with a control group to demonstrate delayed reparation or prompted deformation. We believe that the possibility of a combined factors i.e., external injury and radiation, having contributed to the delay in the healing process should not be precluded, for the cases where the survivors actually suffered injuries from the bombing and that there are no factors - other than those associated with the atomic bomb.
3. Gist of the Statement
The "probability of causation", current criteria for recognition, is merely one of many epidemiological approaches that exist for estimating the probability of a cause having contributed to the formation of a specific illness.
Epidemiology is a science that essentially consists of describing in numeric values phenomena observed in a group of people such as development of a disease or death, to identify the overall regularities of the group by means of inferential statistics.
Therefore, it is a misuse of epidemiology to apply mechanically the “probability of causation” model developed by epidemiological methods to individual A-bomb victims and to deny the causality of radiation, overlooking the specific conditions in which each one of them suffered the atomic bombings.
Medical studies of the time clearly reported cases of distinct acute radiation symptoms among people who were exposed at a distance (distal Hibakusha), or who entered the zone after the explosion (entrant Hibakusha), but who are today denied A-bomb illness recognition because of the misuse of epidemiology. The only reasonable way to explain these symptoms is to admit that residual radiation that is virtually disregarded by DS86, including induced radiation and radioactive products, was present at that time and that it caused significant internal and external exposure.
There are a number of reasons to question the scientific credibility of the fundamental data used in such studies as the Life Span Study (hereafter referred to as LSS) and the Adult Health Study (hereafter referred to as AHS), which the RERF took over from the ABCC.
First, the DS86 primarily provides the estimates of external exposure to initial radiation at proximate distances from ground zero, and is therefore unable to explain the incidence of acute symptoms and late effects observed among distal and entrant Hibakusha in relation with radiation exposure doses.
Secondly, the LSS and the AHS are flawed in their epidemiological approach because they include a large number of distal and entrant Hibakusha in their “non-exposed” or "zero-dose exposed " control groups. They therefore do not provide a genuine comparison between exposed and unexposed populations.
Thirdly, the data used for calculating the “probability of causation” were collected between 1950 and 1986 or 1990, and therefore completely ignore data from the past decade, when incidences of and fatalities from cancer and non-cancer diseases are accelerating.
In the following sections, we will elaborate on the three problems outlined above and present our view on how to understand the survivors' clinical picture and what should be the appropriate criteria for recognition of A-bomb induced disease.
4. Points in dispute regarding A-bomb disease recognition based on the "probability of causation" that solely relies on the DS86
4-1. The mechanical application of the "probability of causation" model to individual A-bomb sufferers to deny the correlation of radiation with their A-bomb disease constitutes a double misuse of epidemiology
A meeting on the “Screening for A-bomb Illness Recognition” held on May 25, 2001 determined the “Guideline on the Screening”. (2)
The Guideline set out a model according to which, for the 13 groups of radiation-related diseases retained for the screening (including other malignant neoplasms) on the basis of the RERF epidemiological studies, their “probability of causation” can be calculated when the age (at the time of the bombing), the sex and the DS 86 radiation dose of a survivor are given.
Such screening method is profoundly questionable in two ways.
First, the epidemiological approach is essentially a science that describes phenomena observed in a particular population in numeric values in order to identify the overall regularities of that population through means of inferential statistics.
Therefore, it is a misuse of epidemiology to present the “probability of causation”, calculated on the single basis of DS86 external radiation dose estimates, as the grounds to rule out the causality between radiation exposure and particular illnesses for each individual Hibakusha.
Second, the “probability of causation” is a statistical value representing the attribution of A-bomb radiation to the development of a particular disease, calculated by using “non-exposed population” as the control group. The decision to assume that a "probability of causation" under about 10% indicates that the disease in question is unlikely to be caused by radiation is unreasonable and untenable. This is the second misuse of epidemiology.
According to the present day medical knowledge, it is believed that, when the human body is exposed to and absorbs radioactive rays, these rays provoke ionization inside and outside the human cells. The products of this ionization and radiation from radioactive particles themselves directly or indirectly damage the DNA in cells (DNA breakage or mutation) or cause DNA repair errors.
Thus, the initial action of radiation on the human body may be described as the destruction of DNA sequences (genomes) in chromosomes. However, experiments have proved that the genomes in damaged cells remain unstable for a long time and after going through cellular divisions for several dozens of generations, the frequency of mutations will increase.
Experiments have also confirmed that these phenomena also occur in low-dose areas and depending on radiation doses. This is not in conflict with the findings of the studies on various radiation victims, including A-bomb sufferers.
For these reasons, the contribution of radiation to the development of cancer and leukemia that are delayed radiation effects is believed to be a stochastic effect without a so-called “threshold”. Therefore, even if the "probability of causation" for a specific cancer is under 10%, the effect of radiation as a cause of that cancer for an individual cannot be completely ruled out. In addition, A-bomb sufferers also underwent internal exposure that is not taken into account in the “probability of causation”. The alpha rays, the major factor of internal exposure, are likely to cause continuous damage through high linear energy transfer at the cellular level.
However, looking at the recent decisions made by the “Screening Committee”, almost no application with a “probability of causation” under 10 % has been accepted. 10% serves as an artificial “threshold” for facilitating a practical screening. Moreover, no scientific explanation is given in any of the official documents as to why the less-than-10% cases had less chance of having been induced by radiation.
As the 60th anniversary of the atomic bombings approaches, research into the effects of radiation on health, i.e. the delayed effects, is more and more focused on cases that are impossible to explain by the “probability of causation” theory. These include the increased incidence of cancer (including multiple cancers), the protracted duration of abnormality in bone marrow and immune function, the increase of so-called benign diseases other than cancers, and genetic effect on the health of the second and third generation Hibakusha.
What is needed for correctly deciding whether a disease of a Hibakusha is caused by radiation or not is to grasp the overall picture of radiation exposure, including internal exposure, and a judgment based on more accurate and longer-term epidemiological studies. The current “probability of causation” model is totally useless for evaluating the association of radiation for individual cases and should therefore be abandoned.
4-2. The plaintiffs are those who were exposed at a distance, or who entered the zone after the explosion. However they were actually exposed to a considerable amount of radiation and sustained damage to their health that cannot be explained by DS86 dosimetry alone
Today, 59 years after the atomic bombing, different health disorders caused by A-bomb radiation are generally classified into a single category of "delayed effects". The delayed effects include disorders caused by slow healing of acute stage trauma and heat injuries, functional disorders such as A-bomb cataracts and keloids, benign diseases such as thyroid disorder and chronic lever disease, and malignant tumors such as leukemia and solid cancers.
On the other hand, in daily clinical scenes, a large variety of diseases, be they benign or malignant, affecting several internal organs simultaneously, are found in many aging Hibakusha. However, it is hardly possible in daily medical practice to determine how significantly the incidences of these heath disorders observed in the Hibakusha group differ from the normal incidences. This is why further epidemiological studies on the delayed effects of atomic bombing are required. What must be also taken into account for these studies is the fact observed in clinical medicine that A-bomb survivors suffering from these delayed effects are not limited to so-called 'proximal Hibakusha'.
It is an established fact today that radiation exposure following the atomic bombing was a compound exposure process. It included exposure to initial radiation generated by nuclear fission, to induced radiation from materials irradiated by neutrons, to the mushroom cloud produced by the nuclear explosion, to radioactive uranium and plutonium particles that did not undergo fission and were carried and scattered in urban areas by smoke from fires and dust from the shock, to the "black rain" containing massive amounts of radioactive fallout, etc.
The findings of several medical surveys made after the atomic bombings, as well as the records left by the doctors who worked at that time, indicate that some distal or entrant Hibakusha, though regarded from the DS86 doses as not exposed to ionizing radiation, also showed acute symptoms that are today called "acute radiation syndrome". In addition to this acute radiation syndrome, various delayed effects or symptoms were observed among these Hibakusha. In order to rationally explain these facts, one cannot but suppose that these Hibakusha underwent not only external exposure to initial radiation, but also both external and internal exposure to induced radiation and the various types of radioactive fallout mentioned above.
Descriptions of the actual condition of radiation disorders of distal or entrant Hibakusha can be found in the valuable findings of studies conducted by doctors and medical researchers of that time.
(1) Masao Tsuzuki, Professor Emeritus at Tokyo University, who went to Hiroshima to investigate after the atomic bombing and later became the responsible officer for the medical group of the Special Atomic Bomb Casualty Commission, wrote in his notes:
"Those who were 2 or more kilometers (less than 4 kilometers) from the hypocenter when the atomic bomb exploded did not at once show any radiation-specific symptoms from that exposure alone (but they can be considered as latent A-bomb injury sufferers). However, when they entered the hypocenter area immediately after the explosion and worked or lived there for some time, many of them developed acute symptoms of radiation disease due to the combined effects of various types of secondary radiations (sic.)". (3)
(2) According to the record of a study conducted from October to December 1945 by the group led by Shirabe, then Professor in the Surgery Department of Nagasaki Medical College, who worked hard in rescue operations although he himself was a victim of the atomic bombing, of 2,828 individuals who were exposed between 2 kilometers and 4 kilometers from the hypocenter (distance for which the kerma doses calculated by DS86 would be less than 12.7 cGy), 77, accounting for 2.7 % of the total, experienced hair loss and 2 of them died during the acute phase. Similarly, pain in swallowing was found in 315 individuals (11.1%).(4)
(3) In Hiroshima, a Japan-U.S. joint medical survey was conducted in October 1945. The survey found that of 5,120 people who worked for this study soon after the atomic bombing (survivors), 707 suffered from hair loss. Of 1,658 of the surveyors who worked within the areas between 2.1 kilometers and 3.0 kilometers from the hypocenter (distance for which the kerma dose calculated by DS86 would be less than 5cGy), 84 (5.0%) suffered from hair loss.(5)
(4) In 1957, 12 years after the atomic bombing, Oho Gensaku, a general practitioner in Hiroshima, surveyed all surviving Hibakusha living in a district of Hiroshima City, using as indicators acute symptoms including diarrhea, fever, subcutaneous bleeding, pharynx pain and hair loss. According to this study, aimed at identifying the presence of residual radiation effects, of the Hibakusha who were outdoors at the time of the atomic bomb explosion and who did not enter the areas around the hypocenter on that day, 142 (43.0%) of 330 distal Hibakusha (i.e. those who were between 2.0 kilometers and 4.0 kilometers from the hypocenter) showed acute symptoms. Loss of hair was reported for 10.9% of those who were exposed at 2.5 kilometers from the hypocenter. The ratio was 12.0% at 3 kilometers, 0.1% at 3.5 kilometers and 2.8% at 4 kilometers. On the other hand, while the incidence of acute symptoms is similar for 214 distal Hibakusha (exposed at between 2.0 km and 4.0 km) who entered the areas around the hypocenter after the explosion (97 (45.3%) of them showed acute symptoms), the incidence of loss of hair is higher for the Hibakusha who entered the hypocenter areas: 7.5% at 2.5 kilometers, 12.2% at 3 kilometers, 7.6% at 3.5 kilometers, 7.6% at 4 kilometers and 9.3% at 4.5 kilometers.
In addition, of 525 individuals who were outside the city and were not exposed to the explosion, but who entered the city immediately after, 230 (43.8%) were identified as having acute symptoms (a rate comparable to distal Hibakusha who were outdoors and exposed to the explosion at between 2 and 4 kilometers from the hypocenter). 4.3% of these were reported to have experienced hair loss.(6)
Similar study results can be found in the "Hiroshima A-bomb War Casualties", a journal published in 1971 by Hiroshima City. The study in question was conducted on 233 officers and soldiers under the Land Army Shipping Command who entered the city immediately after the atomic bombing and carried out rescue operations. It revealed that 120 of those studied (90.2%) showed decrease in white blood cells (diagnosed by army doctors) and 80 (34.3%) experienced loss of hair.(7)
(5) Nagai Takashi, then assistant professor in the Radiology Department of Nagasaki Medical College, who was himself a Hibakusha and injured by the explosion, wrote about the effects of residual radiation on entrant Hibakusha in the following passage in his famous book "The Bells of Nagasaki":
"How about the effects of residual radiation in the areas around the hypocenter? What kind of symptoms do the people who were not in Urakami at the time of bombing and did not suffer any injury and were not exposed the so-called Pika (flash of atomic bomb explosion) develop while living near the hypocenter after the explosion? In order to find answers to these questions, I had a shelter built in Ueno-cho near the hypocenter, began living there and have observed with great attention my surroundings until today. (...) The people who moved into these shelters within three weeks after the bombing began having a sort of severe hangover that lasted more than a month. They also suffered severe diarrhea. Especially those who dug ashes or carried roof tiles to clean up burned houses, or others who worked for the disposal of dead bodies suffered from terrible symptoms. These symptoms were similar to those seen in the patients who were exposed to massive radium radiation. It was indeed a result of a continuous whole body exposure to massive ionizing radiation." (8)
(6) Shigefuji Fumio, one time director of Hiroshima Atomic Bomb Hospital, originally from Saijo (a former district of Hiroshima) and exposed to the explosion inside the Hiroshima railway station building, also worked hard in rescue and relief activities. In an interview with the writer Oe Kenzaburo he spoke of his own experience of the atomic bombing and referred to the acute deaths of several entrant Hibakusha from Saijo who had taken part in relief operations in Hiroshima City. He suggested that their acute deaths were attributable to the effect of ionizing radiation. (9)
Similarly, Hachiya Michihiko, a Hibakusha injured by the atomic bomb and once director of Hiroshima Teishin Hospital, also worked to rescue the A-bomb victims. He wrote about the deaths observed among entrant Hibakusha. (10)
Many of the Hibakusha who have filed the present cases (plaintiffs) are either distal Hibakusha, i.e. exposed to the atomic bomb explosion more than 2 kilometers away from the hypocenter, or entrant Hibakusha. A majority of them were reported to have hair loss, diarrhea, bloody feces, lesions in the mouth, high fever, purple spots and other acute symptoms during the 2 months that followed the atomic bombing. In addition, they suffered from lingering malaise, difficulty in working and other delayed effects. These facts can hardly be explained by direct exposure to initial radiation alone and strongly suggest external and internal exposure to induced radiation and to radioactive fallout.
The findings of a survey recently conducted by Nihon Hidankyo (Japan Confederation of A-and H-Bomb Sufferers Organizations) on 860 distal and entrant Hibakusha indicate that nearly one fourth of them experienced loss of hair and other various acute symptoms. For the Hibakusha, the sufferings caused by these symptoms remain in their memory even after 60 years. (11)
We believe that the panel of the Ministry of Health, Labor and Welfare in charge of screening needs to acknowledge the limits of mechanically applying the method of radiation exposure evaluation based on DS 86 and the "probability of causation", calculated on the same basis, in examining the applications for official acknowledgement of A-bomb disease. This evaluation method underestimates the radiation exposure of entrant and distal Hibakusha and should be corrected.
4-3. Questions and Problems regarding the Basic Documents of ABCC/Radiation Effects Research Foundation Seen from Doctors' Point of View
4-3-1. Questionable process of establishment of DS86 and irrelevance of its use for the evaluation of radiation dose for official recognition of A-bomb disease sufferers
Historically speaking, the very first estimates of radiation doses to which A-bomb survivors were exposed were the provisory dose values (T57D) calculated in 1957. These values correspond to the doses of ionizing radiation present in the air at different distances calculated by the United States on the basis of the data obtained from the nuclear testing conducted in the previous year. Later, these values were corrected by using the data of large-scale testing of Nagasaki-type plutonium bombs and a new set of radiation dose values were proposed by the United States as T65D.
However, on entering the 1970s, with improved techniques for radiation measurement, various problems and contradictions were found in T65D. This prompted its revision.
From 1981 to 1985, a Japan-U.S. joint committee of experts worked to develop a new method and in March 1986, a new radiation dose evaluation system was completed and validated. This new evaluation system was named DS86.
DS86 is a calculation code that combines various physical processes that comprise the following: initial yield of explosion, how radioactive rays diffused, how they propagated in the air, how much buildings or houses shielded radiation, how much radioactive rays irradiated human internal organs etc.
On the other hand, Tajima Eizo, then chairperson of the Japanese committee that dealt with practical matters concerning radiation dose assessment, wrote the following: "To estimate the radiation doses to which the people in these areas (areas where radioactive fallout was especially massive) were actually exposed, one needs to know their actual movements, but such data are not available today. Therefore DS86 does not include the calculation of these doses". (12) What he meant here is that, because of the absence of data, the dose evaluation at that time could not take into account residual radiation and therefore excluded its contribution from the evaluation. However, several dose measurements were performed later by physical methods using the soil samples taken from Koi-Takasu district in Hiroshima City and in Nishiyama district in Nagasaki City, as well as from near the hypocenters in these two cities. In the above-mentioned paper, Tajima estimated that the maximal radiation dose from radioactive fallout for human body tissues would be between 12 and 24 rad in Nagasaki and 0.6 and 2 rad in Hiroshima and that the maximal dose from induced radiation would be approximately 50 rad in Hiroshima and between 18 and 24 rad in Nagasaki. (13)
In another paper, one can find the following passage: "Of the residual radiation, induced radioactivity leads to a small total exposure relative to that from prompt radiation, but it persists over a along period of time, and thus led to both atomic bomb survivors and early entrants being exposed. Also, although the effect due to fission products was localized, it was equivalent to short-term exposure to a dose of the same order of magnitude as long-term exposure to naturally occurring background radiation. (14)
The above paper considers that the effect of nuclear fission products was locally limited. However, there is other research that indicates that, according to the records of the time, nuclear fission products (the black rain) would have fallen over wider areas than has been estimated. Testimonies of some residents and Hibakusha support this hypothesis. Moreover, regarding radioactive fallout, Hibakusha of both Hiroshima and Nagasaki said that in addition to the black rain, radioactive black soot also showered over vast areas. In the case of nuclear tests at the Nevada test site in the United States, where humidity is low, it can be believed that the mushroom cloud did not transform into black rain or black soot, but fell in the form of radioactive micro-particles on the downwind zones. It can be deduced from this that massive amounts of micron-size radioactive particles, invisible to the Hibakusha, might also have spread in Hiroshima and Nagasaki. There is a possibility that these radioactive particles were taken into the human body through respiration and food and caused internal radiation exposure.
After the introduction of DS86, results of new research and new calculations were published regarding unsolved problems and opinions questioning the validity of DS86 increased, pointing to the need to revise the method. Through the work carried out by the Japan-U.S. Joint Commission, the mismatch between the measured values and the estimates obtained by DS86 for short distances from the hypocenter was corrected by raising the height of point zero (the hypocenter) by 20 meters from 580 meters to 600 meters and the new method DS02 was adopted in March 2003.
This is how the dosimetry developed from DS86 to DS02. The major characteristic of this dosimetry development process is that only physical data are used throughout the process: neither acute symptoms seen among Hibakusha nor medical observations of patients in the acute stage are taken into account. For this reason, it has been pointed out that disagreement between DS86 doses and acute symptoms is the major defect of this radiation evaluation method.
Looking into how DS86 was developed, one can see that several physically measured values of exposed materials and the distance of these materials from the hypocenter were used to obtain a curve of radiation dose diminishing with distance. For DS86, the distance covered by initial radiation was estimated at about 2.5 kilometers and it was assumed that the incidence rate of acute symptoms, as well as the mortality rate from disease (incidence rate) of Hibakusha exposed to the explosion within this distance, when compared with the radiation dose estimated by physical methods, should indicate quantitatively the effect on heath of ionizing radiation.
In reality, however, Hibakusha often showed symptoms that did not correspond to the estimates obtained by DS86. This is why dose estimation relying on DS86 alone was questioned in medical practice.
Disagreement between medical observations and dose estimates can be attributed to various causes: problems of the physical measurement itself and, more specifically, the possibility of underestimation of dose beyond 1.4 kilometers and underestimation of exposure to residual radiation and to radioactive fallout that might possibly have affected distal and entrant Hibakusha. These problems are not solved in DS02.
In this regard, a very interesting report was recently presented by a research group of the institute working for the development of A-bomb delayed effects care of Nagasaki University. The report consists of a comparative analysis of the incidence of acute symptoms between two districts located both about 2.5 kilometers from the hypocenter. One is south of the hypocenter and unshielded and the other is north and shielded by mountains. The incidence of hair loss, one of the most characteristic symptoms of radiation exposure, is 1.9% in the shielded district and 5.1% in the unshielded district. Identification of acute symptoms was made by a survey conducted in January 1970. Naturally, the incidences of acute symptoms were significantly lower in the shielded district, but cases of severe hair loss were also observed in the shielded district. The authors of the report point out the possible effect of radioactive fallout observed in this district. (15)
According to DS86, the kerma dose at 2.5 kilometers was only about 2cGy in Nagasaki, but it is a fact that the residents were exposed to a radiation dose sufficient to cause hair loss to 5% of them. The 1988 UNCEAR Report (report submitted by the United Nations Committee on the Effects of Atomic Radiation) indicates that hair loss occurs to between 50% and 90% of the radiation-exposed population at between 2 and 5Gy. According to another set of data that classifies incidence of hair loss among A-bomb survivors by radiation dose, 5% incidence corresponds to approximately 1Gy.(16) As seen above, the fact that DS86 is unable to explain the incidence of hair loss, which is a very specific acute effect of ionizing radiation, is an important medical fact that puts into question the validity of this dosimetry.
The validity of using DS86 dosimetry to estimate the dose to each individual Hibakusha is limited to the assessment of external exposure to initial radiation from neutron and gamma rays at near and medium distances from the hypocenter. DS86 doses are relevant only as the minimum radiation dose to which each Hibakusha was exposed.
In order to assess the total exposure dose for each Hibakusha, taking into account external exposure to residual radiation according to his/her movements after the bombing, as well as internal exposure from drinking water, eating food, relief activities for the wounded and the sick, disposal of dead bodies, clean-up of debris etc., we believe that at least some acute symptoms such as hair loss need to be taken as biological indicators, separate from the data used for DS86, and these indicators need to be included in the evaluation process to obtain a more comprehensive radiation dose estimate.
4-3-2. Kodama Paper, which provided the basis for the "probability of causation", does not reflect the evolution of mortality and incidence rates of the last 10 years
(1) The work that provided the theoretical basis for the "probability of causation" is the "Study on the Assessment of the Health Effects of the Atomic Bomb Radiation on Human Body", a health science research project led by Kodama Kazunori, then Professor in the Faculty of Medicine, Hiroshima University (hereafter referred to as Kodama Paper). (17)
Concerning cancer, Kodama Paper indicates that the authors used as their reference the report of RERF Review LSS No.12 (18), which analyses the cancer mortality survey conducted from 1950 to 1990. This report states that the survey of the incidence of solid cancers relates to the period 1958 to 1987. This means that calculations were made using reports that were already more than 10 years old.
We believe that the method used for the analysis of significant differences in incidence found in LSS data is fundamentally defective and we will discuss these defects later. In this section, we will discuss about how to explain the changes that have occurred in these significant differences.
(2) According to the reports published before LSS No.10, during the period from 1945 to 1979, the malignant diseases that were identified to show a statistically significant difference in their incidences due to radiation exposure were leukemia, lung cancer, thyroid cancer and breast cancer. These reports also suggested a relation with radiation exposure for stomach cancer, esophageal cancer, urinary cancer, salivary gland cancer, malignant lymphoma and multiple myeloma.
In LSS No.10 (1950-1982), a statistically significant difference in incidence was reported for leukemia, esophageal cancer, stomach cancer, colon cancer, lung cancer, breast cancer, urinary cancer (excluding kidney) and multiple myeloma. Malignant lymphoma did not show any significant increase. The LSS No.10 also indicated that during that period, the increase rate of excess relative risk for prostate cancer became the highest of any other malignant tumors and that the mortality rate for spleen cancer was significantly high in Nagasaki.
LSS No.11 (1950-1985) reported a significant difference in incidence for leukemia, esophageal cancer, stomach cancer, colon cancer, lung cancer, breast cancer, ovarian cancer, urinary cancer (excluding kidney) and multiple myeloma. What is new is the addition of ovarian cancer to the list and the removal of thyroid cancer from the list.
LSS No.12 (1945-1990) on which the Kodama Paper is based, for the first time listed liver cancer in addition to leukemia, esophageal cancer, stomach cancer, colon cancer, lung cancer, breast cancer, ovarian cancer, bladder and urinary tract cancer and multiple myeloma.
In the latest issue of LSS, published in October 2003 (LSS No.13 from 1950 to 1997, hereafter referred to as LSS No. 13) (19), a significant increase is found in the incidence of cancers that until LSS No. 12 had not shown any significant difference in excess relative risk, including rectal cancer (female), gallbladder cancer (male) and brain/central nerve cancer (male).
It should be noted that even in the case of pancreatic cancer, uterine cancer and colon cancer (male), whose incidence does not show any significant difference according to LSS No.13, the median of 90% confidence interval of excess relative risk is positive.
The LSS reports published after its No.11 issue do not mention anything about the mortality rate from thyroid cancer, but two papers (Reference 33 and “Cancer incidence in Atomic Bomb Survivors. Part II Solid Tumors, 1958-1987, by Thompson et al.) published in 1994 confirm its significant increase.
(3) As shown above, we must pay attention to the fact that the number of human body regions affected by cancer with significantly higher incidence increases on every LSS issue.
RERF researchers themselves indicate: "Data concerning Hibakusha suggest that excess risk of virtually every type of cancer can be considered to be related to ionizing radiation. Regarding solid cancers, approximately 50 percent of excess deaths during the period from 1950 to 1990 occurred during the last 5 years" (20). In fact, 19 percent of deaths from solid cancers and 15 percent of deaths from other diseases occurred during the 7 years from 1991 to 1997, the period after the publication of LSS No.12.
It is known that the risk of solid cancers of A-bomb survivors tends to increase at ages favorable for the development of each type of cancer. From this, one may expect that the risk will increase for many cancers as the Hibakusha grow older.
These medical facts will be discussed again in 4-3-4 of the present statement. They indicate that some diseases, be they solid cancers or non-cancer diseases, only begin to show a statistically significant difference in mortality rate from 1990, more than 45 years after the exposure to the atomic explosion. Therefore, even if a significant difference is not apparent in the LSS data compiled until 1997, the possibility that an obvious increase might appear later cannot be excluded. This is also made evident by the following quote from a RERF researcher: "It is generally well known that a number slightly exceeding half of the LSS cohort of the RERF survey had died by the second half of the 1990s. However, it is not very well known that many of the deaths related to ionizing radiation (excess deaths) in the LSS cohort are yet to occur". (21)
4-3-3. DS86: Irrationality from medical point of view of the decision to turn down applications based on the data provided by the Radiation Effects Research Foundation
This section shows the irrationality, in light of established medical knowledge, of using the RERF's "probability of causation" that puts DS86 dose evaluation as precondition, to refuse to recognize the A-bomb disease.
(1) As shown by analysis earlier, damage from the radiation of the atomic bombs is considered to have been caused by the multiple pollution of (a) initial radiation, (b) induced radiation generated by neutrons, and (c) radioactive fallout. Radioactive fallout contained products of the nuclear explosion such as fission products, fissile material as uranium or plutonium, which was left unexploded, and nuclei of the bomb container or equipments that turned to induced radiation by neutrons. Taking the form of radioactive particles, black rain and dust, the fallout fell over an extensive area.
The estimate of the dose response by the Life Span Study (LSS) group of the ABCC, however, addresses only external exposure to initial radiation, while disregarding the internal radiation caused by radioactive fallout and residual radioactivity. It therefore fails to reflect effects of the multiple pollution by many sorts of radioactive materials, nor does it take into account the acute symptoms, i.e., the biological expression of the effects on the human body. The dose estimate of DS86 cannot explain epilation, bleeding from the gums or other parts of the mouth, diarrhea, fever, purple spots, the loss of teeth and other acute symptoms that haunted people who suffered at distant places from the epicenter (distal Hibakusha) or those who later entered the city and were affected (entrant Hibakusha).
It was often the case with the distal Hibakusha or entrant Hibakusha that they entered the city as soon as it became possible to engage in relief work or in search of their families or relatives, and that they touched bodies, living or dead, clothes and the rubble contaminated with radioactivity, or that they walked around the center of the explosion every day, including while cleaning up the ruined city. It is possible that they were exposed to internal irradiation from the contaminated water and food they took into their bodies. The multiple exposures to the radiation around that time as described above lie in the background of the occurrence of the acute symptoms, which DS86 is unable to explain.
It is therefore clear that the concept of the excess relative risk worked out on the basis of this faulty dose assessment system does not properly reflect the damage in reality.
(2) The study of Hibakusha is valuable as an attempt to elucidate the aftereffects of the radiation from the A-bombs on the human body. However, as Iijima Soichi already pointed out 25 years ago, the epidemiological study by the Atomic Bomb Casualty Commission (now, the Radiation Effect Research Foundation) has serious flaws and it contains limits and problems in its interpretation. (22)
As of now, it has three major problems.
The first one is that the calculation of the dose is based on DS86, which is limited to the estimate of the dose in the air and shielded kerma of the initial radiation. This has already been discussed in Section 4-3-1.
The second problem is that in selecting a group of non-sufferers as a control group, needed to calculate "excess relative risk," an artificial method has been used since the 1980s.
The third problem is that the survey in question began in 1950. For the five preceding years, a considerable number of A-bomb sufferers had died. Therefore, from an epidemiological viewpoint, the possibility that it is affected by a statistical bias because the group of people surveyed were made up of those who had been able to survive the period, i.e., the possibility of the calculated risk being underestimated, is not excluded.
Of these, the second problem, in particular, is very important. Since the selection of a control group is of vital importance, it directly affects the "excess relative risk," which is the very core of the "probability of causation".
At first, the basic control groups of LSS and AHS were made up of those people who were at the same age and of the same sex as those who suffered within 2km, including about 26,000 citizens of Hiroshima or Nagasaki who were not in either city at the time of the A-bombing and were, therefore, not exposed to the radiation (Not In City = NIC). In the 1970s, it was found that the mortality rate of the control group made up of NIC from both cancer and other diseases was lower than the mortality rate of the so-called Zero-dose Hibakusha who received 0.005Gy, i.e., 5mGy or less (of whom, many were distal Hibakusha, but some 25% were those who were caught within 3km when the bomb struck). In the 1980s and onwards, NIC were removed from the control groups on the ground that there was a differential in the mortality rate between the groups, whose cause was “unknown”.
An underlying problem of this decision seems to be the following: The study in question excluded from the beginning the assumption that the differential between the NIC group (categorized as “non-Hibakusha”) and the Zero dose group might have resulted from the possibility that the Zero dose group people were significantly exposed to radiation, and it decided to seek the cause of the differential of mortality in the gap in the social and economic conditions of those days following the A-bombing between the two groups. Its interpretation was that the distal Hibakusha were mainly those who lived in rural areas and were poorer than proximal Hibakusha living around the center of the city. In other words, for a reason different from the effects of the bomb, it assumed that the mortality rate of the group was from the beginning higher than the other group. As evidence of this assumption, the study quotes the data of LSS, which shows the standardized mortality rate (SMR) became higher the more remote it was from the epicenter after 1950. The data showed that the SMR of the Zero Dose Group of people, who were within 3km from the epicenter on the day of the A-bombing was the lowest.
It is not clear if such assumption is still held by the RERF now. But recent reports released by the RERF observe that they cannot deny the possible "effect of the selection of healthier Hibakusha", meaning that the closer it was to the epicenter, the more citizens died by 1950, and as the result, relatively healthier Hibakusha happened to survive. It indicates that this survey includes inexplicable contradictions in selecting the control group members. (23)
We believe that the selection of the control group in LSS study as referred to above thus imposed a fatal flaw on the entire epidemiological study aimed at analyzing the effect of radiation, including low-level radiation, on the human body.
In brief, we want to emphasize that, because of the erroneous selection of the control group, the problems of the exposure to radiation of both distal and entrant Hibakusha, who had been categorized as having been exposed to less than 0.005Sv (Zero Dose Group) by the DS86, which disregards the effects of internal irradiation or residual radiation, have been neglected from the beginning.
As seen above, various contradictions are produced by the fact that the group of those who suffered from 0.005Sv or less dose of radiation, namely the so-called "Zero Dose" group, was inappropriately used as the control group in conducting LSS and AHS. Even another document of RERF admits that in the same Zero Dose group, a clear differential has appeared in the morbidity rate of cancer between those who were exposed to the blast at 3km or farther and those within the radius of 3km (the morbidity rate of the distal Hibakusha at 3km or farther is higher)(24). This means that RERF itself actually admits that determination of the risk only by means of its dose assessment based on DS86 does not reflect the actual depth of damage.
Various reasons can be given as to the background in which the RERF chose the people, including those affected by low-level radiation, for the control group. But it is a hard fact that the RERF has clung to the assumption that the exposure to radiation of 0.005Sv or less does not have any meaningful effect. As one of the reasons, it can be assumed that the true objective of both LSS and AHS themselves at the beginning was to study the effect of the initial radiation alone to serve military medicine.
4-3-4. In screening A-bomb disease applications, emphasis should be put on the actual conditions under which the applicants were exposed to the bombing as well as their clinical picture. Their applications should not be turned down on the grounds of a low “probability of causation”
Nearly 90% of the plaintiffs are those who suffered from the bombing at age 20 or younger. About 30% of them suffered at age 10 or younger.
Regarding the effect of the radiation on the incidence of cancer, it is reported that the younger you were when you suffered from radiation, the higher the rate of death from cancer is. This applies to all types of cancer except for leukemia in terms of both relative and absolute risks. (25)
Report 13 (19), the latest report of LSS, says that of all who are subjects of the LSS, 91% of those who were at 9 or younger at the time of the bombing, 80% of those having suffered between 10 and 19, and 66% of those between 20 and 29 are still alive. To know what effects will appear in these "younger" Hibakusha, we have to wait for the outcome of future studies. In the same way, 90% of those who received 0.1Sv or smaller dose, calculated on the basis of DS86, are alive, and therefore we need to wait for future studies to know about what effect will appear on the Hibakusha who were affected at 1.95km or farther from the epicenter in Hiroshima, or at 2.1km or farther in Nagasaki. It is inappropriate to ignore or deny the risk of delayed effect, particularly of cancer, on Hibakusha affected at distant places or having entered the contaminated city, now when still many Hibakusha are alive.
Here we present our view on some specific diseases:
(1) A-bomb victims are highly likely to develop not only a single kind of cancer but multiple cancers
The diseases of the plaintiffs for which they applied for recognition are of various kinds. Yet, out of 146 plaintiffs as of July 2004, those contracting cancers or malignant tumors (including brain tumors) are as many as 94. Their cancers are of 25 different kinds.
The risk of Hibakusha contracting solid cancer varies depending on the sex, age at the time of the A-bombing, and elapsed years since the A-bombing. Increase in cancer risk among younger Hibakusha is generally confirmed, and the tendency is that the incubation period of their cancer is long, and that the dose-dependent increase is not as conspicuous as in the case of leukemia or those who were exposed to the A-bomb after age 20. In other words, in the case of younger Hibakusha, the fact that they were exposed to the A-bomb itself, even with a low dose of radiation, constitutes the risk of developing cancer.
The cancer risk of the Hibakusha over 20 at the time is believed to increase in proportion to the increase of cancer mortality of their age peers. Now that over 50 years have passed since the A-bombing, many Hibakusha have reached the age at which people are prone to cancer, and the increase of particular cancer among them coincides with that among the general population.
Set below is a breakdown of the sorts of cancers, including brain tumors, which 78 of the plaintiffs have contracted. (Figures are the number of plaintiffs who contracted a particular cancer).
Gastric cancer (13); lung cancer (9); prostate cancer (8); liver cancer (7); thyroid cancer (5); rectal cancer (4); kidney cancer (4); breast cancer (3); bladder cancer (3); skin cancer (3); malignant lymphoma (2); multiple myeloma (2); colon cancer (2); pharyngeal cancer (2); esophageal cancer (2); bile duct cancer (2); pharyngeal cancer (1); cancer at papillary area of the duodenum (1); adult T-cell lymphocyte leukemia (1); malignant melanoma (1); brain tumor (1); pituitary gland tumor (1); cancer of uterine body (1).
As seen above, various kinds of cancers have appeared among the plaintiffs, which include those reported to have no significant difference in their occurrence from the general population in the latest LSS report discussed in 4-3-2. This possibly indicates that among these cancers, there are some with a long incubation period or a low mortality rate. Also it is possible that, according to the multiple-phase theory of cancer development, some of the cancers have no conspicuous difference in mortality between Hibakusha and non-Hibakusha, depending on the gravity of accelerators that were added to the patients after the time of the atomic bombing. Some cancers might not have developed if the patients were not exposed to the A-bomb.
Another distinctive point is that 21 (22.3 %) of the plaintiffs have contracted double (multiple) cancers.
The following breakdown shows the kinds of the multiple cancers. This includes both the cancers for which the plaintiffs have applied for recognition of an A-bomb disease and the cancers for which they had contracted but did not make application.
Stomach cancer plus esophageal cancer plus lung cancer; breast cancer plus stomach cancer plus ovarian cancer plus uterine cancer; malignant lymphoma plus breast cancer plus ovarian cancer; double stomach cancer; stomach cancer plus esophageal cancer; stomach cancer plus colon cancer; stomach cancer plus rectal cancer (2); stomach cancer plus lung cancer; lung cancer plus liver cancer; lung cancer plus rectal cancer; stomach cancer plus bladder cancer (2); bile duct cancer plus bladder cancer; pharyngeal cancer plus esophageal cancer; liver cancer plus thyroid cancer; ureteral cancer plus prostate cancer; prostate cancer plus skin cancer. Other than the diseases mentioned above, there is one applicant who applied for the recognition of having an A-bomb disease for hypothyreosis, but who had a history of double cancers of stomach and the breast.
Regarding the double cancers, Professor Tomonaga Masao of the Atomic Bomb Disease Institute of the School of Medicine, Nagasaki University, emphasized in his contribution to the conference of physicians of the designated medical institutions in 2002, "Recently physicians engaged in medical treatment of A-bomb sufferers report the tendency of patients contracting two different cancers or more... As A-bomb sufferers were exposed to radiation over their whole body, it is easily gathered that multiple organs were damaged by the radiation." (27) He thus pointed out a need for further study of the problem.
There have been many other study reports that also point out that the cases of multiple cancers are particularly many among A-bomb sufferers, the fact that has attracted the attention of many clinicians and researchers. Of them a report presented by Sekine and other researchers of the A-bomb Disease Institute of Nagasaki University to a symposium on the delayed effects of the A-bomb held in 2004 is especially noteworthy. (28)
The Sekine report is about a large-scale study of the subject based on the data of cancers contracted by the surviving victims who were registered in Nagasaki Prefecture's cancer registry. As most of the data are based on the preserved pathological samples, the outcome of their studies can be said to be highly accurate. According to their report, they established that of about 18,600 cases of cancer of the Hibakusha registered in 37 years from 1962 through 1999, 663 had multiple cancers, and that the rate of multiple cancers in all cases rose in inverse proportion to distance to the epicenter. The report thus recognized the correlation between the dosage of radiation and multiple cancers. Also among important facts are that this tendency became increasingly tangible since 1988, and that the rate of multiple cancers is higher among those who suffered from the bomb when they were young. This suggests that there will be more cases of multiple cancers in the future. The increase in multiple cancers among the Hibakusha shows that it is inappropriate and even meaningless to refer to the "probability of causation" of each separate cancer. In the case of the cancers of the Hibakusha, it is essential to bear in mind the possibility that even if one is cured of one cancer, another may attack him/her. Because this is a serious problem, the recognition of the A-bomb disease on these Hibakusha's cancers must be granted without delay.
(2) Incidence of prostate cancer is possibly high among A-bomb sufferers
The RERF's LSS Report, even in its latest 13th issue, does not acknowledge any significant increase in the mortality from prostate cancer. Perhaps because of this, most of the applications for the recognition of A-bomb disease based on their prostate cancer have been turned down. However, even if there was no increase in the mortality rate from prostate cancer as of 1997, as was reported by the 13th issue, this does not necessarily serve as a reason to deny the causality of radiation for prostate cancer.
There are four reasons for this: (1) because the progress in diagnosing and treating prostate cancer has possibly lowered the mortality rate or has delayed death; (2) because prostate cancer is a cancer that happens in men of advanced age, it needs a long observation period until any significant difference in mortality appears; (3) it is also not negligible that some proportion of Hibakusha die from other diseases before they reach certain ages at which the incidence of prostate cancer is high; and (4) the LSS' morbidity study has been conduced referring to the diseases recorded in the death certificates and the cancer registry. But it is possible that prostate cancer does not appear in either of these two records. In other words, the possibility of not a small number of oversights or wrong diagnoses being recorded cannot be excluded.
According to a recent report from the Hiroshima Red Cross Hospital & A-bomb Survivors Hospital in Hiroshima, the group of distal and entrant Hibakusha was the highest in the incidence of the prostate cancer as against all histopathological diagnoses in the period from April 1988 to January 1997, followed by the group of proximal Hibakusha, then by the non-Hibakusha group. Between the group of distal and entrant Hibakusha and the group of non-Hibakusha, the positive reaction of the former is twice as high. This shows the possibility that prostate cancer occurs more frequently among the Hibakusha than non-Hibakusha. This same tendency was found in examining only the aged Hibakusha at 70 and beyond. This study concluded that, "prostate cancer at an advanced stage is found more frequently from every aspect among the group of distal and entrant Hibakusha." (26) This outcome of the study apparently calls into question the present operation of the MHLW Screening Committee, which dismisses the "significant difference" solely on the basis of the RERF's reports on mortality.
Further, this study also suggests that the group of "Zero Dose", chosen as a control group in the RERF's epidemiological study referred to in 4-3-3, are the people affected by the residual radioactivity and marking a higher incidence of prostate cancer, and that the RERF's epidemiological study on prostate cancer, therefore, is no longer applicable.
(3) Recent Increase in the mortality and morbidity of diseases other than cancer
Regarding the effect of the A-bomb radiation exposure on diseases other than cancer, only in the late 1960s, 20 years after the A-bombing, a significant increase in the incidence of such diseases has began to be reported.
The first report on the increase in the mortality of non-cancer disease patients was released in the LSS Report 11 (1950-85) made public in 1991. The report said that after 1965, over 20 years after the A-bombing, among the Hibakusha who were under 40 years of age at the time of the A-bombing and whose estimated dose of radiation exposure was above 2Gy, a significant increase in the mortality rate was observed among patients of cardiovascular diseases (mainly heart disease and cerebral apoplexy) and digestive system diseases (mainly cirrhosis). (29)
This tendency was further increased as stated in the LSS Report 12 (1950-90) made public in 1998. There, a 10% increase in the death risk per 1Sv was noted, and this increase was also observed in respiratory system diseases (mainly non-tuberculous pneumonia), following cardiovascular and digestive organ diseases. What is more, the difference in the increase among different ages at the time of A-bombing is absent here, and even in the low-dose area, this dose relationship is recognized.
The latest LSS Report 13 (1950-97) revealed that the risk of non-cancer disease mortality during the 30 years of follow-up period had increased at a rate of about 14 % per 1Sv, and that the estimate value of the excess risk of non-cancer diseases has come closer to that of cancers.
Further, a significant increase in non-cancer disease incidence was found in the AHS Report 7 (1958-86) published in 1992 and Report 8 (1958-98) published in 2003. (30, 31)
AHS Report 7 recognizes a significant excess risk in hysteromyoma, chronic hepatitis, cirrhosis and benign diseases of the thyroid gland. There, the significant findings on hysteromyoma and benign thyroid diseases can be regarded as ones that suggest a possibility of the development of benign tumors caused by radiation exposure, and are drawing attention to their future development. The increase in the incidence of chronic hepatitis and cirrhosis naturally proves the radiation sensitivity of the liver once again and coincides with the recent increase in mortality due to cirrhosis. The risk of diseases of the thyroid gland is increasing especially among those who were under age 20 at the time of the A-bombing, clearly attesting to the radiation sensitivity of the thyroid among younger people. Moreover, it is to be noted that this risk has been unchanged all through the follow-up period of the A-bombing.
The latest edition, AHS Report 8, which analyzed the 12 years of follow-up period in addition to the analysis in previous issues, recognized the significant increase of additional diseases -- cataracts, hypertension, heart infarction of those A-bombed at age under 40, male renal and ureteral calculus. Among them, cataracts used to be regarded as not having a significant difference in previous editions, but after the 12 years of follow-up study, a significant increase by dose was recognized.
Among the146 Hibakusha plaintiffs, 52 are seeking official recognition on their non-cancer diseases. It seems that it is not a coincidence that among them are chronic hepatitis, cirrhosis, thyroid gland diseases, cataracts, heart infarction and cerebrovascular disorders, diseases for which a death and morbidity increase were recognized in the recent reports of LSS and AHS. Also observed was the fact that burn scars and functional disorders caused by glass fragments are still inflicting pain on the Hibakusha. Most of the applications involving such non-cancer diseases have been rejected. We cannot but believe that these applications are rejected en mass (by the Ministry of Health) without indicating any scientific grounds, despite that fact that these diseases are proved to be increasing according to the recent reports.
(4) Radiation causality of benign thyroid gland diseases
There has been a great deal of medical knowledge strongly suggesting the radiation causality of hypothyreosis. A research in Nagasaki suggests that thyroid nodule shows the relation with dose response, while significantly more cases of hypothyreosis are found among the group of those exposed to a relatively low dose of radiation, i.e., below 50rad (0.5Gy). (32) This strongly suggests the possibility that hypothyreosis is likely to develop among the entrant Hibakusha who were exposed to induced radiation or fallout. Chronic thyroiditis, which is a kind of autoimmune hypothyreosis, did not clearly show radiation causality in the study of an earlier period, but later studies recognize the increase of the disease among the Hibakusha of Nagasaki.(33) The hypothyreosis developing after surgery on malignant lymphoma of the thyroid, which is considered to be a complication of thyroid nodule or chronic thyroiditis (Hashimoto's Disease), ought to be recognized officially (as A-bomb induced disease), as long as radiation causality of the primary disease cannot be denied. As already mentioned, both AHS Report 7 and Report 8 report a significant increase of benign thyroid gland diseases.
(5) Radiation causality of chronic hepatitis and cirrhosis
Already shortly after the A-bombing, some medical doctors noticed many cases of liver diseases among A-bomb victims. Attesting to this fact, as in LSS Report 11 and AHS Report 7 onwards, an increase of deaths and morbidity of liver diseases has consistently been reported. The ruling of the Tokyo District Court in favor of the plaintiff is still fresh in our minds, in which the plaintiff with chronic type-C hepatitis had sought A-Bomb disease recognition.
In the background of many cases of chronic hepatitis and cirrhosis is persistent infection with type-C hepatitis virus (HCV). RERF reports so far have pointed out that despite the absence of a significant difference among Hibakusha's rate of positive response to HCV antibody, there is a possibility that their radiation exposure and persistent infection with the virus have worked as joint factors that have contributed to the progress of hepatitis. These reports also found an increase in the rate of positive response to Type-B hepatitis virus antigen among the Hibakusha under age 20 exposed to above 1Gy of radiation. This can be regarded as indicating that the Type-B virus infection of the Hibakusha is not fully controlled by the immune system, suggesting that Type-B hepatitis has radiation causality. On the question of radiation causality of liver disorders, Dr. Saito Osamu of Fukushima Coop Hospital submitted the Statement (1) (34) as documentary evidence of the plaintiff to Tokyo District Court for Azuma A-Bomb Lawsuit, which has given a detailed argument.
(6) Radiation causality of cataracts among the A-bomb victims
In the past, many cases of cataracts suspected of having radiation causality were characterized as those that developed several months after the A-bombing, or the irradiation cataracts caused by delayed development of opacitas of the posterior subcapsular part in the posterior pole of the lens among younger Hibakusha, or the senile cataracts by premature cortial opacitas. Some ophthalmological opinions on the plaintiffs' applications also record such findings.
In the latest AHS Report Vol. 8, a significant dose response to cataracts was again reported. Also, at the 44th Meeting of the Atomic Bomb Aftereffects Study Group held in 2003, it was reported that "In the findings on the effect of radiation exposure on the crystalline lenses of the atomic bomb survivors, a significant relationship was observed with delayed irradiation cataracts and early senile cataracts".(35) This is important knowledge that suggests the possibility that the delayed development of irradiation cataracts, which have been regarded as being caused by the deterministic effects of radiation, may fall under the stochastic effects of radiation, which may also suggest the radiation causality of cataracts of the plaintiffs.
(7) Burn injury and post-traumatic disorders
The primary burns from the atomic bomb heat rays led to the formation of keloids, which in later period caused joint contractures or skin disorders. The formation of keloids by primary burns has characteristic pathological findings, and it has been determined that radiation has a cause-effect relationship on this.
The arthrosis deformas or post-fracture disorders of the plaintiffs, though they themselves cannot be regarded as directly caused by radiation, clearly have their origin in the damaging effects of the atomic bomb disaster, including their exposure to radiation. The possibility of radiation-induced immune disorder causing the delay in their pathological healing mechanism should be taken into consideration. Also, as a result of multiple adverse conditions in the chaotic post-A-bombing situation that prohibited the plaintiffs from normal recovery, the healing process might have been significantly delayed, leaving them with such functional disorders as deformation of humeral articulation or the lower limbs.
(8) On determination of the need for medical treatment of the diseases of the plaintiffs
The opinions of the physicians in charge should be fully respected in determining the needs of the plaintiffs' injuries and diseases. Especially, those who have malignant diseases such as cancers, although they have undergone surgeries, strongly wish to receive continuous health consultation and medical checks on possible recurrence or exacerbation of their diseases. Their doctors also acknowledge the medical necessity of such care. The postoperative period of five years, the old standard period that has still been designated for the follow-up observation to control the recurrence of cancers, cannot be regarded as a sufficient time to remove the fear of the A-bomb victims. A longer follow-up period is necessary for the A-bomb survivors, in light of the fact that a relatively large number of cases of allochronic and multiple cancers are observed among them.
5. Our views on the clinical pictures of the A-bomb victims' diseases to be officially recognized
5-1. Need for transformation of the administration of the recognition system based on the real suffering of the victims
Today, even 59 years after the atomic bombing, many questions are still left unresolved in the health problems caused by the exposure to the atomic bomb radiation. The need for careful medical treatment to ensure the physical and mental health of the atomic bomb victims, who have survived into the 21st century, has gone unchanged.
The atomic bomb survivors, now in their old age, still have great anxiety over possible development of delayed health problems such as cancers or malignant tumors, and thus have great expectations about governmental measures based on the "Law on the Relief of Atomic Bomb Sufferers" to support their living and medical care. Also, with wars caused by major nuclear powers continuing and the existence of nuclear weapons showing no signs of being abolished, many A-bomb survivors are again feeling fear and anxiety.
In such situations, their desire to receive official recognition of their A-bomb diseases will not likely stop as long as they live.
We, the physicians in the medical institutions in charge of the medical treatment and health care of the Hibakusha feel that we cannot turn our eyes from the contradictions in the present recognition administration, especially, the man-made barriers that justify rejection based on the "probability of causation". As set below, we state our views on the current government administration on the official recognition of A-bomb diseases.
5-2. Solid cancers and malignant tumors should be recognized as A-bomb induced unless there is a clear alternative cause
Scientific knowledge of humans on the relationship between the intensity of exposure dose and its effects on human body on the molecular genetics level is not yet perfect. However, recognition of the fact that the stochastic effect on cancerogenesis, as was already discussed in 4-1, can be applied to the low-dose area, has been established by many, including the researchers of the RERF who have analyzed the data of the LSS. There are still no grounds to believe that the exposure to low-dose radiation is sufficiently safe for the future of human beings.
Therefore, due legitimacy should be recognized on the part of the atomic bomb survivors seeking the cause of their cancers in the atomic bombing, even if they were exposed to a low dose of radiation.
The unilateral determination of non-presence of cause-effect relations below 10% of the "probability of causation" (for example, 1500mSv for a male stomach cancer patient who was A-bombed at age 12) of DS86, which takes into consideration only initial A-bomb radiation, is strongly questionable and contradictory, when it is compared with the current governmental administration of labor accidents. The government recognizes the radiation-induced occupational diseases of the workers who are exposed to an annual average of over 5mSv of radiation, as stated in the Notice of the Labor Inspection Bureau Chief (No. 810) concerning the "Ordinance on Prevention of Ionizing Radiation Hazards".(36)
5-3. The current list of illnesses designated as A-bomb induced should be made more inclusive
A person who was in the past in a condition to be externally exposed to initial A-bomb radiation or radioactive products, or internally exposed to residual radiation (absorption or suction of radioactive fallout into the body) and later had such acute symptoms as fever, diarrhea, bleeding from gums, stomatic diseases, loss of teeth or hair, or subcutaneous bleeding, which are regarded as the deterministic effects with threshold values, is naturally believed to have been exposed to a considerable amount of radiation, whether distally or as an entrant.
Even if they had no memory of such acute symptoms or were too young to remember the time of the A-bombing, many of them should be regarded as having been exposed to such radiation, given the location where they actually were or the actions they took after the A-bombing, or the conditions under which they entered the city. Therefore the absence of memory of experiencing acute symptoms should not be the reason for their applications being turned down.
The current clinical pictures of delayed health disorders actually seen among the Hibakusha individually are nothing but general diseases, including solid cancers, and there are no measures to medically determine whether or not they have been caused by the effects of the A-bomb radiation. Therefore, as long as no alternative reasonable explanation can be found regarding the development of these diseases, affirmative consideration should be given to recognize their cause-effect relations with the A-bomb radiation, based on the standpoint of the “Treatment Guideline”.
Given these preconditions, not to mention the diseases of which significant increase is recognized in the recent LSS or AHS reports suggesting the effects of radiation, we believe that even the diseases of which significant increase is not yet recognized should be recognized as A-bomb induced, as long as no other relevant cause can be found.
5-4. Appropriate requirements for the recognition of A-bomb illness
As in the foregoing, we have described our critical views on the current recognition system of the A-bomb diseases based on the "probability of causation" theory. Then, what should be the conditions for recognizing the diseases as A-bomb induced, based on the medical knowledge involving the A-bomb survivors? Set below, we have sorted out the conditions of the applicants who should be officially recognized:
(1) The exposure to the A-bomb radiation or its effects on the body can be presumed
a. The applicants presumed to have been exposed to initial radiation (gamma rays or neutrons) released by the nuclear reaction of the atomic bomb (the fact of being proximally exposed as recognized in DS86).
b. The applicants presumed to have been exposed to gamma rays, beta rays or alpha rays from the radioactive products or fallout (the fact of being externally or internally exposed due to the black rain, fire smoke, radioactive fine particles deriving from disposal of corpses or debris, and contaminated food or water).
c. The applicants presumed to have been exposed to the induced radiation (radiation from the soil, concrete or iron frames).
d. The applicants have a history of experiencing physical signs within about 2 months of exposure to the A-bomb radiation (fever, diarrhea, bleeding tendency such as bloody stools or bleeding from gums, gingivostomatitis not easy to cure, loss of hair, purple spots or lingering malaise)
e. The applicants suffer the formation of keloids after burn scars or traumatic cicatrix
f. The applicants have leukopenia or liver function disorders develop within several years of the A-bombing (including B-type hepatitis patients and those showing positive reaction to C-type hepatitis test)
g. The applicants had the so-called "Bura-bura disease" symptoms, which persisted for a long time after the A-bombing such as systemic fatigue, poor health, amnesia, or difficulty to continue working (Easy fatigability peculiar to the A-bomb victims, whose relationship with internal irradiation is suspected, but has not been fully elucidated). (37)
(2) Applicants are suffering from one of the following: Tumors in hematopoietic organs such as leukemia developing after the A-bombing; malignant tumors such as multiple myeloma, osteomyelodysplasic syndrome or solid cancers; or tumors in the central nervous system.
(3) Applicants cannot be denied to be suffering from the aftereffects of the A-bomb radiation, and that they are recognized as having health problems as below that need medical treatment
a. Cataracts in which opacitas in the posterior subcapsular part or cordical opacitas are confirmed.
b. Having heart disease, such as heart infarction; cerebral apoplexy; lung disease; liver function disorder; disease in the digestive organs or hematopoietic disorders such as delayed leucopenia and severe anemia, and that the cause-effect relations with the exposure to radiation cannot be denied, without any other strong cause in one's medical history.
c. Medical treatment is needed for hypothyreosis or chronic thyreoiditis.
d. Presence of motor function disorder due to the delay in curing traumatic injury sustained on the day of the A-bombing, or disorder caused by glass fragments or exogenous material in one's body.
We believe that when the applicant's exposure to the A-bomb radiation or its effects on the body can be presumed by any one of the items in (1), and any one of the health problems in (2) or (3) is confirmed to be currently in the state of needing medical treatment, the applicant should be recognized as suffering from A-bomb induced disease. Even those having the disease of which significant increase has not been observed in the LSS or AHS reports, as long as no other influential cause is found in differential diagnosis, should also be recognized.
Also, even if the applicant has no record of suffering acute symptoms, due attention should be given to the fact that the rate of development of acute symptoms from proximal exposure to the A-bombing was not 100% because of the difference in individual sensibility, and that there have been cases of loss of memory due to the shock from the A-bombing, or that it was difficult for the young Hibakusha under age 10 to remember the situation in which they were A-bombed.
In this paper, we have made clear the illegitimacy of rejecting the application based on the "probability of causation", of the limitation of dose evaluation by DS86, of the fact that the entrant and distal Hibakusha were also exposed to considerable doses of radiation, all attesting to the scientific basis and reasonableness in the claims of the Hibakusha who have filed the case calling for the reversal of the rejection on their A-bomb disease recognition.
Further, we have shown the characteristic clinical pictures of the health problems caused by the exposure to the A-bombing, trying to suggest the ways and conditions for A-bomb disease recognition, which are convincing for us as doctors.
By rights, the "Law on the Relief of Atomic Bomb Sufferers" should have the nature of providing state compensation to the Hibakusha, who have survived through suffering from radiation damage, long-time neglect by the government and social discrimination. However, the actual state of the A-bomb recognition system, which the Hibakusha would turn to as the last stronghold, has been so removed from the desires of the Hibakusha.
Also, in order for Japan, the only A-bombed country, to appeal for the conclusion of an international treaty to abolish nuclear weapons, giving careful and good care and help to the Hibakusha, still suffering from the damage from radiation even 59 years later, is indispensable.
It is our sincere wish that in the current lawsuit for the A-bomb disease recognition, the desires of the plaintiffs will move the Courts, and the decisions rendered will serve as heartful recommendations to the Ministry of Health and Labor.
List of Citations and References
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|| LSS Report 11 (1950-85)
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|| Nagataki Shigenobu, et. al., “Thyroid diseases among atomic bomb survivors in Nagasaki”, JAMA, Aug 1994 (English version)
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|| “Atomic Bomb Disaster in Hiroshima and Nagasaki”, page 159