Population-based epidemiological study of primary intracranial tumors in childhood

Brain tumors are the most common solid tumors in children and their prognosis is poor. Epidemiologic data from a population-based cancer registry provide the information necessary to determine the incidence rate of pediatric brain tumors. The aim of this study was to determine the epidemiology of childhood primary intracranial tumors in Kumamoto Prefecture, Japan. We surveyed 210 patients younger than 15 years who were diagnosed with primary intracranial tumors between 1989 and 2008; 159 (75.7%) of the tumors were confirmed microscopically. The age-adjusted annual incidence rate was 36.1 cases per million children. The boys/girls ratio was 1.31. The age-specific annual incidence rate was 28.5-, 40.9-, and 38.4 cases per million for the 0- to 4-, 5- to 9-, and 10- to 14-year age group, respectively. The incidence was highest in 10- to 14-year-old boys (53.6 per million) and lowest in 10- to 14-year-old girls (22.6 per million). The most common tumor was astrocytoma (35.7%) with an annual incidence rate of 13.2 per million, followed by germ cell tumor (14.3%, 5.0 per million), craniopharyngioma (10.5%, 3.8 per million), medulloblastoma (10.0%, 3.7 per million), and ependymoma (4.8%, 1.5 per million). The distribution of the tumor type varied with the patient age and gender. Although there were no germ cell tumors in 0- to 4-year-old boys, they were the second-most common tumor in 10- to 14-year-old boys. Conversely, while there were no medulloblastomas in 10- to 14-year-old girls, their incidence was high in 0- to 4-year-old girls. In this Kumamoto survey, the incidence rate of primary intracranial tumors in children was similar to that in Western countries. However, the incidence and relative frequency of particular histological types of childhood brain tumors such as germ cell tumors and craniopharyngiomas were different between Japan and Western countries.