SURG-14. LOWER-GRADE GLIOMA IN ELDERLY PATIENTS: TREATMENT AND OUTCOMES IN A MOLECULARLY CHARACTERIZED CONTEMPORARY COHORT

Abstract

Abstract Lower-grade glioma (LGG) is rare among patients above the age of 60. Previous series reported poor outcomes, likely due to a high proportion of missed IDH wildtype astrocytomas which today would be diagnosed as glioblastoma, and thus proposed defensive treatment in elderly patients. We questioned these findings in our contemporary cohort of “true” LGGs, i.e. IDH mutant astrocytoma and oligodendroglioma WHO grade 2 and 3. Patients aged 60 years and older (“elderly”) treated for hemispheric LGG were retrospectively analyzed for demographic, tumor- and treatment-related factors and progression-free survival (PFS) and were compared to a cohort of patients younger than 60 years. Inclusion criteria, amongst others, were availability of molecular data and volumetric assessment of pre- and postoperative tumor burden. 212 patients were analyzed, among those 21 elderlies (9.9%). Elderly patients did not differ from younger ones regarding preoperative tumor volumes, eloquent location, presence of contrast enhancement and clinical presentation (seizures, focal deficits). In both groups (elderly vs. younger), most patients underwent tumor resection (81% vs. 90.6%; p=0.25) with comparable median residual tumor volumes (5.12 cm3 vs. 3.28 cm3; p=0.66). There was a trend towards more aggressive surgical approaches in younger patients, e.g., use of IOM and awake surgery. However, rates of functional deterioration (p=0.2) and revision surgery (p=0.98) were comparable. Oligodendroglioma, in relation to astrocytoma, was more common in the elderly (76.2% vs. 46.1%; p=0.011). Adjuvant radio- and/or chemotherapy was administered in 76.2% of elderly and 59.8% of younger patients (p=0.163). Median PFS was comparable (50 vs. 56 months; p=0.62), regardless of WHO grade (p=0.43) and tumor subtype (p=0.93). In conclusion, favorable surgical and survival outcomes were achieved in our series that were comparable to those of younger patients. Thus, intensified treatment including maximal safe resection should be advocated in elderly patients whenever feasible.