["International cooperation in cancer research" research on radiation carcinogenicity]

Since it is impossible to estimate radiation carcinogenesis in man, particularly its type and the magnitude of risk, from data obtained from animal experiments, it is necessary to conduct studies directly using epidemiological data on human populations. In addition to A-bomb survivors, populations subject to occupational exposure and medical exposure are considered as samples for epidemiological study of radiation carcinogenesis. With regard to A-bomb survivors, the Japanese National Institute of Health and the Atomic Bomb Causality Commission (ABCC) of the U.S. initiated joint programs in 1947, two years after the bombings, and they have energetically engaged in research activities since then. Especially after 1950 a fixed population of approximately 110,000 individuals, composed of A-bomb survivors and non-exposed subjects as controls, was established and a large-scale epidemiological prospective study has been conducted for a long-term follow-up of the population. In 1970 the JNIH-ABCC was reorganized as the Radiation Effects Research Foundation, a joint U.S.-Japan research organization, but the research programs have been continued. The results are often cited as the most reliable data available in the reports of both the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR report) and the U.S. Committee on the Biological Effects of Ionizing Radiation (BEIR report), and are also regarded as important data in the calculation of permissible dose (dose limit) by the International Commission on Radiological Protection (ICRP). Scientists from various countries other than the U.S., such as the United Kingdom, Israel, the People's Republic of China and Indonesia in the capacity of visiting research fellows have engaged in collaborative studies in the fields of epidemiology, immunology, cytogenetics and pathology at the REF Recently a British biostatistician, engaged in an analysis of the follow-up study for a fixed population of approximately 20,000 individuals who underwent radiotherapy for ankylosing spondylitis in the United Kingdom, joined the Foundation to make a comparative study of research data concerning a fixed population of A-bomb survivors, especially the mortality rate from cancer, using the same analytical method as that employed in England and confirmed that the developmental pattern of radiation-induced cancer is almost the same in the two populations. This is one typical example of the collaborative studies being carried out. At present, reassessment of radiation dosimetry, which provides a basis for risk estimation, is being conducted with the cooperation of radiation physicists in U.S. and Japan.(ABSTRACT TRUNCATED AT 400 WORDS)