Racial patterns of childhood brain cancer by histologic type.

Racial patterns of childhood brain cancer by histologic type were studied using data from the Third National Cancer Survey and the Surveillance, Epidemiology, and End Results Program. Incidence rates for whites of all types combined and of astrocytic glioma and medulloblastoma were slightly higher than those for blacks. Proportionately more black than white cases of astrocytic glioma were diagnosed between the ages of 5-9 years; this difference corresponded to twofold-higher rates at ages of 0-4 and 10-14 years and similar rates at ages of 5-9 years among whites compared to rates among nonwhites. A real difference in age-incidence curves rather than diagnostic delay among blacks appeared to explain the differences. For medulloblastoma, the male-female rate ratio differed between whites (1.7) and blacks (1.0). Time trend analyses revealed statistically significant increases in medulloblastoma and glioma not otherwise specified (NOS) for incidences among blacks. The rate of microscopic confirmation was significantly higher among whites than among blacks, a difference apparently not explained by differences in the accessibility of tumors for biopsy. For avoidance of biased comparisons, differences in rates of microscopic confirmation and time trends for glioma NOS should be considered in studies of racial patterns of childhood brain cancer incidence by histologic type.