Risks and Benefits of Glioblastoma Resection in Older Adults: A Retrospective Austrian Multicenter Study

Abstract

Objective: To assess the prognostic profile, clinical outcome, treatment-associated morbidity, and treatment burden of elderly patients with glioblastoma (GBM) undergoing microsurgical tumor resection as part of contemporary treatment algorithms.

Methods: We retrospectively identified patients with GBM ≥65 years of age who were treated by resection at 2 neuro-oncology centers. Survival was assessed by Kaplan-Meier analyses; log-rank tests identified prognostic factors.

Results: The study population included 160 patients (mean age, 73.1 ± 5.1 years), and the median contrast-enhancing tumor volume was 31.0 cm³. Biomarker analyses revealed O(6)-methylguanine-DNA methyltransferase-promoter methylation in 62.7% and wild-type isocitrate dehydrogenase in 97.5% of tumors. The median extent of resection (EOR) was 92.3%, surgical complications were noted in 10.0% of patients, and the median postoperative hospitalization period was 8 days. Most patients (60.0%) received adjuvant radio-/chemotherapy. The overall treatment-associated morbidity was 30.6%. The median progression-free and overall survival were 5.4 months (95% confidence interval [CI], 4.6-6.4 months) and 10.0 months (95% CI, 7.9-11.7 months). The strongest predictors for favorable outcome were patient age ≤73.0 years (P = 0.0083), preoperative Karnofsky Performance Status Scale score ≥80% (P = 0.0179), postoperative modified Rankin Scale score ≤1 (P < 0.0001), adjuvant treatment (P < 0.0001), and no treatment-associated morbidity (P = 0.0478). Increased EOR did not correlate with survival (P = 0.5046), but correlated significantly with treatment-associated morbidity (P = 0.0031).

Conclusions: Clinical outcome for elderly patients with GBM remains limited. Nonetheless, the observed treatment-associated morbidity and treatment burden were moderate in the patients, and patient age and performance status remained the strongest predictors for survival. The risks and benefits of tumor resection in the age of biomarker-adjusted treatment concepts require further prospective evaluation.

Keywords: Adjuvant treatment; Biomarker; Elderly; Glioblastoma multiforme; Outcome; Resection; Treatment-associated morbidity.