Recent advances in molecular and genetic diagnostics cardinally changed the classification of GBM. The genomewide analysis revealed mutations of isocitrate dehydrogenase 1/2 genes (IDH1/IDH2) in some of these tumors, particularly in the ones evolving from lower-grade gliomas. This is of a particular interest as IDH1/IDH2 mutated GBM generally has better outcomes. MGMT is another mutation that is associated with improved PFS and OS.

A retrospective chart review was performed for all patients admitted over the period from September 2014 to September 2019 with the diagnosis of GBM. Only patients younger than 45-years-old were included in the study. The primary endpoint was OS and PFS. Secondary endpoints were age at presentation, location, IDH1/IDH2 status, MGMT status and other molecular mutations.

Patients were divided into Group 1 (IDH1/IDH2 wildtype, primary) and Group 2 (IDH1/IDH2 mutant, secondary). Treatment history, MGMT status, complications and outcomes were reviewed.

A total of 15 patients were included in the study. Mean follow-up was 17.3 months (1 to 60 months).

Group 1 included 9 patients whereas Group 2 included 6 patients. Mean age in both groups was 29 years old (14 to 41). In Group 1 MGMT methylation was present in 2 patients (22%), median OS was 7 months and median PFS was 4.4 months. In Group 2 MGMT was methylated in 2 patients (33%), median OS was 15.5 months and median PFS was 5 months.

Patients younger than 45 years old possibly have better OS and PFS, likely due to higher proportion of IDH1/IDH2 mutated GBM compared to general population. Our sample size is too small for statistically significant conclusions. Larger population-based studies are needed to prove these findings.