Incidence and Survival of Childhood Cancer Cases Diagnosed between 1998 and 2000 in Hiroshima City, Japan

Abstract

There have been few studies on cancer incidence and survival among children in Japan. Childhood cancercases in Hiroshima City can be ascertained almost perfectly in terms of completeness and validity as both apopulation-based cancer registry and a tissue registry cover the whole area. We report here recent incidenceand survival of childhood cancer in Hiroshima City. Subjects were cancer patients less than 15 years of age inHiroshima City registered in the Hiroshima City Cancer Registry and/or the Hiroshima Prefecture TumorRegistry (tissue registry) between 1998 and 2000. Cancer incidence in Hiroshima City was calculated for 12diagnostic groups according to the International Classification of Childhood Cancer, and compared with generalincidence in Japan. Five-year survival was calculated by the Kaplan-Meier method. There were 63 children whohad a cancer newly diagnosed during 1998-2000, with only one death-certificate-only case (1.6%). Agestandardizedincidence rates (per million) was 144.3 for boys and 93.9 for girls. Leukemia was the most frequent(29%) among the 12 diagnostic groups. There were 13 cancer deaths during this period and five-year survivalwas 79% (95% Confidence Interval: 67%-87%). Childhood cancer incidence was slightly higher than that forall of Japan, but the relative distribution of patients by diagnostic group was compatible with the general pattern.Both of these observations might be due to the high quality of the tumor and tissue registries.