Mortality of Brain Tumors During Childhood in Japan

Abstract

Background: In general, the leading cause of death due to malignant neoplasms during childhood is leukemia. The next one is brain tumors. In Japan, this situation has continued for a long time. Recently, however, it is changing, with a decrease in the mortality rate of leukemia and increase in that of brain tumors. Methods: Data on neoplasms of the brain in 5-year age categories were obtained from the 1960 to 2013 vital statistics of Japan (e.g., C71 in ICD 10). The data for subcodes from C71.0 to C71.9, which indicate the original site, and the data on leukemia were employed as well. Populations and the number of live births were obtained from the census and vital statistics of Japan. Results: (1) Mortality rate: Not only the age-adjusted mortality rate of brain tumors for all ages but also each of the crude mortality rates at 0-4, 5-9 and 10-14 years of age has been increasing. (2) Site of the tumors: The correlation coefficient between the crude mortality rate of tumors in the brain stem and the year was significantly positive (0.751). That of tumors in the cerebral ventricles was also significantly positive (0.534). However, that for tumors in the cerebellum was negative (-0.448). (3) Mortality rate by birth cohorts: The crude mortality rate by birth cohorts at 0-4 years of age as a whole has been increasing since 1960. (4) Comparison with leukemia: At 0-14 years of age the crude mortality rate for brain tumors has been higher than for lymphoid and myeloid leukemia since 1999 and 1990, respectively. Conclusion: In Japan, the age-adjusted mortality rate of brain tumors and the crude mortality rates during childhood have been increasing, though the causes remain unidentified. Their incidence may be increasing. The recent increase in the crude mortality rate of brain tumors during childhood cannot be explained by the progress in diagnostic methods, the use of a mobile phone or parental smoking. It is speculated that the incidences of pontine glioma and ependymoma are increasing. The leading cause of death at 0-14 years, as well as at 0-9 years of age, will be brain tumors in the near future.