Impact of location on outcome in children with low-grade oligodendroglioma

Childhood low-grade oligodendroglioma (WHO grade II) are rare. No controlled pediatric study has been published, to generate high level evidence for the best treatment. Therefore, we retrospectively analyzed data available from pediatric patients.

We pooled data from two prospective German multicentre studies (HIT-DOK and HIT-LGG). Eligibility criteria were: (1) primary neoplasm, (2) histology of pure oligodendroglioma WHO grade II, (3) intracranial location, (4) age <18 years, (5) date of diagnosis: 1990-2002, (6) observation time >6 months. The outcome was analyzed by using the SPSS-software.

Nineteen boys and 13 girls were eligible (median age 10.3 years). The tumor locations included: 26 peripheral tumors (23 cerebral hemisphere, 3 cerebellum), and 6 central tumors (4 thalamus, 1 frontal mesencephalon, 1 basal ganglia). Resections were classified as complete in 18 (14 cerebral hemispheres, 3 cerebellum, 1 thalamus) and less than complete in 14 patients (3 subtotal resections, 8 partial resections, 3 biopsy). The 5-year event-free survival (EFS) and overall survival (OS) rates of all patients were 81.3 and 84.4%, respectively (median observation time 3.8 years). All of the 26 children with peripheral tumors were alive with no tumor progression, but five of six patients with central tumors died of disease (median time to death 1.6 years). This survival difference was statistically significant for EFS (P < 0.0001) and OS (P < 0.0001). The difference between completely resected versus incompletely resected tumors was far less striking (P > 0.06).

The outcome of children with centrally located low-grade oligodendroglioma is particularly poor, while tumors of the cerebral hemispheres and cerebellum carry an excellent prognosis, even with minor tumor resection.