Proposal of a scoring scale as a survival predictor in intracranial oligodendrogliomas

Histological, clinical and radiological features, and molecular genetic analysis are among the factors that have been considered in defining the prognosis of oligodendrogliomas (OD), but they have yielded conflicting results. The purpose of this study was to test out a scoring scale based on clinical, radiological, pathological and molecular features.

To identify factors with prognostic significance, we analyzed 87 treated patients with a histological diagnosis of OD. Of the parameters analyzed, age, onset, clinical status, radiological enhancement, histological necrosis, mitosis and chromosomal anomalies emerged as significant prognosis factors using univariate analysis. Multivariate analysis revealed age and chromosomal anomalies as independent factors of survival.

The factors with a significant prognostic value were combined to determine which grouping factors best predict outcome. The proposed score is a pure number resulting from a combination of: 2 major factors: age and chromosomal anomalies (scored 3-0); 5 minor factors: onset, clinical examination, necrosis, mitoses (scored 1-0), and radiological enhancement (scored 2-0). According to our scale, 10 survival curves were produced for overall survival. Recursive partitioning of patients with the nearest score and outcome produced four groups with a significant difference in survival (p=10(-5)). The power of both the scale and the partitioned groups for predicting outcome was more accurate than the WHO and St Anne grading systems, and the molecular sub-classification.

Our scale is a plausible way of classifying patients harboring intracranial OD according to expected survival.