Quantitative histologic factors for grouping childhood supratentorial neuroglial tumors

The histologic heterogeneity of childhood supratentorial neuroglial tumors, when quantified, identifies relatively homogeneous subgroups for prognostic purposes and for assignment in clinical trials. Our sample consisted of supratentorial tumors in the Childhood Brain Tumor Consortium. The data consist of reliably identified histologic features and demographic, clinical, operative, and survival information. Factor analysis was used to identify uncorrelated "factors," each represented by a different combination of histologic features in 703 tumors. The defining histologic features were used to label each factor. The heterogeneity of each tumor was summarized using the factor scores for each factor. We compared the survival estimates of subgroups of tumors within common diagnostic classes. We identified five uncorrelated quantitative factors that accounted for much of the histologic variation. Our factor labels were Jumbo, Fibrillary, Proliferative, Spongy, an Oligodendroglial. Two thirds of tumors had high scores on two or more factors, indicating a high degree of heterogeneity among these tumors. Eighty-four percent of supratentorial tumors were accounted for by 19 nonoverlapping relatively homogeneous histologic groups. The five quantitative factors complement standard qualitative taxonomies by summarizing more completely the histologic feature aspects of a tumor than by diagnosis alone and quantify the histologic heterogeneity of individual tumors. Histologically homogeneous groups of tumors are essential for clinical trials, biologic research, and prognostic models.