Age-related Changes in Diagnoses, Histological Features, and Survival in Children with Brain Tumors

In the Childhood Brain Tumor Consortium database, the proportions of older children (> or = 11 yr) with pilocytic astrocytomas, fibrillary astrocytomas, and ependymomas significantly increased (P < 0.05) over the 50 years (1930-1979) of the study. The increased proportions of pilocytic astrocytomas occurred whether the tumors were located in the supratentorial or infratentorial compartments. The increases in fibrillary astrocytomas and ependymomas were found only within the supratentorial tumor location. Some histological features found in pilocytic astrocytomas (e.g., Rosenthal fibers, granular bodies, and very low cell density) were more likely to be found in older children. Other histological features were also more likely to be found in older children (e.g., parenchymal calcification, intertwined fascicles, intermediate and large-size nuclei, pleomorphic, elongated, or irregular nuclei, prominent nucleoli, multinucleated cells, thick hyaline blood vessels, hemosiderin, and parenchymal and perivascular lymphocytes). The probability of 5-year survival for young children with supratentorial ependymomas remained at approximately 0.4 in contrast to that for young children with infratentorial ependymomas, for whom it improved, but without significant linear trend. The probability of 5-year survival for both younger and older children with primitive neuroectodermal tumors (medulloblastomas) improved, but without significant linear trend. The changes in the proportions of childhood brain tumors and histological features occurred without similar changes in the proportions of older and younger children in the cities involved between 1930 and 1979. These changes were so distinctive as to raise the possibility of significant shifts in environmental exposures in younger and older children over the 50 years of this study.