CANCER INCIDENCE IN ATOMIC-BOMB SURVIVORS .1. USE OF THE TUMOR REGISTRIES IN HIROSHIMA AND NAGASAKI FOR INCIDENCE STUDIES

More than 30 years ago, population-based tumor registries were establi shed in Hiroshima and Nagasaki. This report, the first of a series of papers on cancer incidence, describes methodological aspects of the tu mor registries and discusses issues of data quality in the context of the Life Span Study (LSS) cohort, the major atomic bomb Survivor popul ation. The tumor registries in Hiroshima and Nagasaki are characterize d by active case ascertainment based on abstraction of medical records at area hospitals, augmented by tissue registries operational in the area and a number of clinical and pathological programs undertaken ove r the years among the atomic bomb survivors. Using conventional measur es of quality, the Hiroshima and Nagasaki tumor registries have a deat h certificate-only (DCO) rate of less than 9%, a mortality/incidence ( MII) ratio of about 50%, and a histological verification (HV) rate in excess of 70%, which place these registries among the best in Japan an d comparable to many established registries worldwide. All tumor regis try data pertaining to the LSS population were assembled, reviewed and handled with special attention given to the quality and uniformity of data based on standardized procedures. Special studies and monitoring programs were also introduced to evaluate the quality of the tumor in cidence data in the LSS. Analyses were performed to examine the qualit y of incidence data overall and across various substrata used for risk assessment such as age, time and radiation dose groups. No significan t associations were found between radiation dose and data quality as m easured by various indices. These findings warrant the use of the pres ent tumor registry-based data for studies of cancer incidence in the a tomic bomb survivors.