Definitive classes of childhood supratentorial neuroglial tumors. The Childhood Brain Tumor Consortium.

Our objective in this study was to identify histologically homogenous classes of childhood supratentorial neuroglial tumors. Previously, we identified five quantitative histologic factors (differing linear combinations of 17 reliably recognized histologic features in neuroglial tumors). They account for much of the histologic variance in the 703 supratentorial tumors in the Childhood Brain Tumor Consortium (CBTC) database. In this study, we used the scores on the factors in cluster analyses and identified eight classes of neuroglial tumors. Each of these classes had significant differences in histology, allowing the separation of many of the conventional types of neuroglial tumors into two or more classes. For instance, fibrillary astrocytoma, pilocytic astrocytoma, subependymal giant cell astrocytoma, anaplastic astrocytoma, oligodendroglioma, and ependymoma were represented in two or more classes. Often these classes had statistically significant differences in survival distributions. For instance, the two classes of "anaplastic astrocytomas" have widely discrepant 5-year survival probabilities of 0.7 and 0.2. Use of the classes identified in this study ensures relatively homogeneous histologic subsets of tumors. We suggest that these classes will be useful for the selection of children for therapeutic clinical trials.