Childhood leukemia: Epidemiological investigation and effectiveness of treatment in Nagasaki over the past 12 years

Abstract

An epidemiological investigation of childhood leukemia was performed in Nagasaki Prefecture. The objective of this investigation was to analyze the disease as a whole by studying (i) the incidence classified by year, sex, area and disease type, (ii) age of onset, (iii) effectiveness of treatment, (iv) prognosis, and (v) possible association with the atomic bombing in 1945. The annual incidence was 3.0 per 100 000 children under 15 years of age, lower than the national average. There was no significant change in the annual incidence for 12 years. No increase in incidence was observed in Nagasaki City and its surrounding areas. There was no obvious difference in age of onset and incidence by sex from those previously reported. Acute lymphocytic leukemia accounted for a large part of childhood leukemia. There was no increase in the incidence of acute non-lymphocytic leukemia, but its familial occurrence and accumulation were observed. The rate of first complete remission and the number of long-term survivors increased with the improvement of treatment for acute leukemia. The influence of the atomic bomb was not clear when the incidence of disease types was compared between areas. The comparison of the disease type ratio in patients of the second and third generations of atomic bomb victims with that of patients without a family history of atomic bomb exposure also did not show an obvious influence of the bomb.