Epidemiological analysis of childhood cancer in Japan based on population-based cancer registries, 1993-2009.
BACKGROUND
There are few recent data on trends in childhood cancer incidence using population-based cancer registries in Japan.


METHODS
This study comprised 6110 reported cases of patients aged 0-14 years who were diagnosed as having primary cancer between 1993 and 2009. We chose cancer registries of seven prefectures, according to the international cancer registry standard of fewer than 10% death certificate only cases among cancer registries in Japan. We analyzed population-based cancer registration data in the seven prefectures between 1993 and 2009. We calculated childhood cancer incidence, age-specific incidence, crude incidence rate, age-adjusted incidence rate, confidence intervals and annual change for each prefecture and classified the data into 12 diagnostic groups, according to the International Classification of Childhood Cancer (ICCC).


RESULTS
According to sex-specific incidence, males accounted for slightly more cases than females. Children 0-3 years old accounted for 41.1% of patients. Leukemia accounted for 36.0% of cancers, followed by central nervous system tumors with 15.0%, according to the ICCC. The crude incidence rate did not change substantially, remaining at an average 8-11 per 100 000 population. In addition, the age-adjusted incidence rate remained constant with an average 2 per 100 000 population.


CONCLUSIONS
Using population-based cancer registry data, age-specific incidence and 12 diagnostic groups according to the ICCC showed characteristics of childhood cancers. The incidence rate of childhood cancers has been nearly stable in Japan over the past 15 years.
Department of Mathematical Health Science, Course of Health Science, Graduate School of Medicine, Osaka University, Osaka.
Hiroyuki
H
Ishihara
Department of Mathematical Health Science, Course of Health Science, Graduate School of Medicine, Osaka University, Osaka.
Yuko
Y
Ohno
Department of Mathematical Health Science, Course of Health Science, Graduate School of Medicine, Osaka University, Osaka.
Makoto
M
Fujii
Department of Pediatric Hematology and Oncology Children's Medical Center, Osaka City General Hospital, Osaka.
Junichi
J
Hara
Radiation Effects Research Foundation Nagasaki Laboratory, Nagasaki, Japan.
Midori
M
Soda
D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D009369:Neoplasms / Q000453:epidemiology*; D012042:Registries
childhood cancer; epidemiology; incidence; population-based cancer registry