Contribution of Japan Children’s Cancer Registry to Medical Research and Care of Childhood Leukemia and Related Conditions

Abstract

The Japan Children’s Cancer Registry was established in 1969 as an annual nationwide survey to clarify the status not only of mortality, but also morbidity in childhood malignancies and among long-term survivors. We found that childhood leukemia, which is the most frequent malignancy, accounted for 43% of the total cases in this hospital-based registry. Leukemia showed male dominance and an age peak at 2–3 years, whilst most solid tumors showed no sex predominance and an age peak within 12 months after birth. High concordance in monozygotic twins and a high incidence of specific chromosomal translocation were observed in leukemia. These findings suggest that the etiological mechanism of leukemia differs from some blastomas in which loss of heterozygosity of the genes has been reported. Heterogeneity of leukemia was also suggested by comparisons of characteristic features, among types classified both by FAB and immunological markers, in relation to age distribution, sex ratio, type of chromosomal aberration, frequency of complication of Down syndrome, and family history. The registry will continue to contribute to the study of the etiology and biological nature of leukemia, as well as to the improved care of children with leukemia in general.