gms | German Medical Science

Objective: Low-grade diffuse glioma 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 surgery in elderly patients. We questioned these findings in our contemporary cohort of true lower-grade gliomas (LGG), i.e. IDH mutant astrocytoma and oligodendroglioma WHO grade 2 and 3.

Methods: Patients aged 60 years and older (“elderly”) treated for hemispheric LGG between 2009 and 2019 were retrospectively analyzed for demographic, tumor- and treatment-related factors and progression-free survival (PFS) and were compared to a cohort of LGG patients younger than 60 years at diagnosis. Inclusion criteria, amongst others, were availability of molecular data (IDH mutation, 1p/19q co-deletion, ATRX expression) and volumetric assessment of pre- and postoperative tumor volumes.

Results: 212 patients met inclusion criteria, among those 21 elderly patients (9.9%). Elderly patients did not differ from younger ones regarding gender, tumor eloquence, preoperative tumor volumes, 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, frequency 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), mainly in WHO grade 3 tumors. In patients with a minimum follow-up of 2 years (n=144), median PFS was comparable between elderly and younger patients (46 vs. 55 months; p=0.58), regardless of WHO grade (p=0.31) and tumor subtype (p=0.81).

Conclusion: Elderly patients still constitute a small fraction of molecularly characterized LGGs. In contrast to previous reports likely including IDH wildtype tumors, 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.