The histologic grade is a main prognostic factor for patients with intracranial ependymomas treated in the microneurosurgical era: an analysis of 258 patients.

BACKGROUND: Ependymomas account for 3-5% of all intracranial malignancies and occur most often in children and young adults. These neoplasms continue to generate considerable controversy with regard to their rational clinical management. It has been shown that the histologic classification of ependymoma is a significant predictor of clinical outcome in patients with ependymoma.

METHODS: Ependymomas from 258 patients who underwent microsurgery at a single institution were evaluated histologically to elucidate the prognostic utility of a recently proposed grading scheme. Pathologic and clinical data then were compared using univariate and multivariate analyses.

RESULTS: Increasing grade of ependymoma malignancy was found to be associated strongly and independently with worse clinical outcomes in terms of both event-free survival and overall survival. The effect of radiotherapy also was found to be related to histologic grade and was more beneficial for patients who had anaplastic ependymomas and had undergone complete tumor removal.

CONCLUSIONS: The application of a uniform diagnostic criteria for grading ependymomas highlighted the key role of tumor histology in clinical outcome in a cohort of patients who were treated in the microsurgical era. The recently proposed grading scheme is likely to be practically useful, reproducible, and clinically applicable.