SURVIVAL OF CHILDREN WITH INFRATENTORIAL NEUROGLIAL TUMORS

OBJECTIVE: The goal of this study is the improvement of the prognostic information associated with conventional diagnoses. Our previous fact or analysis of 26 reliably identified histological features in infrate ntorial childhood neuroglial tumors yielded five interpretable, uncorr elated, quantitative histological factors that we named spongy, fibril lary, proliferative, nuclear, and ring. Five quantitative scores, one for each of the five factors, provide an objective method for quantify ing the histological heterogeneity of a tumor. The scores, alone or in conjunction with conventional diagnoses, identify groups of histologi cally homogeneous tumors. METHODS: Multivariate Cox proportional hazar ds models were developed to assess the contribution of each factor to survival prognosis, after allowing patient-specific demographic and cl inical data in the models as covariates. Hazard ratios, estimated for each statistically significant factor and covariate in the multivariat e model, provide the basis for the determination of the prognosis. The hazard ratio is the ratio of the hazard function for subjects with an attribute, e.g., an age of 10 years, to the hazard function for subje cts who have some chosen baseline attribute, e.g., an age of 1 year. T he important criterion of this ratio is beta, a statistic estimated fr om the survival data in the Childhood Brain Tumor Consortium database of infratentorial neuroglial tumors. Kaplan-Meier survival curves were used to investigate differences in the survival of factor-determined subgroups of patients with various diagnoses. RESULTS: An increased li kelihood of survival is associated with older age, more tumor removal, more recent decade of surgical intervention, and high spongy and fibr illary factor scores. A decreased likelihood of survival is associated with high nuclear, proliferative, and ring factor scores. Gender, loc ation within the infratentorial compartment, and subsequent treatment did not add prognostic information. For certain subgroups of astrocyto ma and for ependymoma and medulloblastoma, factors are important in pr edicting survival with greater accuracy. CONCLUSION: Factor scores pro vide clinically useful quantitative estimates of survival probability that are more specific and accurate than the general estimates based o n the conventional diagnosis alone.