Characteristics, outcome, and prognostic factors of young patients with central nervous system World Health Organization grade 3 oligodendrogliomas IDH-mutant and 1p/19q codeleted: A French POLA network study

Abstract

Background

Brain tumors represent one of the main causes of cancer-related mortality in young patients. Among them, oligodendrogliomas (OG) are adult-type diffuse gliomas with the best prognosis. Nevertheless, characterization of these tumors in the young population remains poorly documented. Our objective was to characterize the population of young adults under 40 years of age with grade 3 OG in the POLA cohort.

Methods

Clinical data prospectively collected for all patients registered with grade 3 OG between April 2009 and August 2021 were extracted from the national POLA database. This study compared the patient subgroup <40 years of age to the one >40 years of age.

Results

The authors included 111 patients <40 years old and 363 patients ≥40 years old. Treatment received did not differ significantly between the two subgroups. Temporal location was more frequent in older patients (p = .009). Patients <40 years old presented more often seizure as initial symptom (p = .003). They had less frequent chromosome 9p loss (p < .001) and less CDKN2A homozygous deletion (p = .024). Median progression-free survival (PFS) was 123 months (range, 86–not reached [NR]) versus 88 months (range, 67–117) (p = .082) and median overall survival (OS) was not reached (range, 147–NR) versus 163 months (range, 137–NR) (p < .001) in younger and older subgroups, respectively. In multivariate analysis, complete or subtotal resection (p = .014) and seizure at diagnosis (p = .032) were associated with better OS.

Conclusion

Young patients with grade 3 OG have distinct clinical presentation, molecular features, and outcomes compared to the older patients.