NCOG-04. Predictors of preserved independence in GBM patients aged 80 or older

Abstract BACKGROUND There is ongoing debate regarding the optimal treatment strategy for elderly patients with glioblastoma (GBM). Advanced age is a known poor prognostic factor, and many patients experience a decline in functional independence after treatment due to limited recovery. However, some individuals maintain independence level in the chronic phase. This study aimed to identify preoperativepredictors of preserved independence in GBM patients aged 80 or older. METHODS We retrospectively analyzed 30 patients aged ≥ 80 years (mean age: 82.9) with newly diagnosed GBM, all followed for at least 3 months. The mean preoperative Karnofsky Performance Status (KPS) was 68.7%. Surgery included biopsy (n = 11) and tumor resection (n = 19). KPS and neurocognitive functions were assessed preoperatively and at 3 months postoperatively. We examined factors influencing chronic KPS using univariate and multivariate regression analyses, along with receiver operating characteristic (ROC) analysis. RESULTS KPS significantly declined at 3 months compared to preoperative values (p = 0.0052). Main causes were reduced physical activity (30%), cognitive decline (28%), and muscle weakness (26%). Among preoperative factors, tumor location was significantly associated with preserved independence; patients with temporal or parietal tumors were more likely to maintain higher KPS scores (p = 0.016). Additionally, higher chronic-phase KPS was correlated with better preoperative Mini-Mental State Examination (MMSE) scores. ROC analysis identified an MMSE cutoff of 15. Patients with MMSE ≥ 15 had a significantly greater likelihood of maintaining KPS ≥ 70 at 3 months (p = 0.035). Using tumor location and MMSE, independence could be predicted with high accuracy (sensitivity: 83.3%, specificity: 94.4%, AUC: 88.7%). CONCLUSION In GBM patients aged ≥ 80 years, those with tumors in the temporal or parietal lobes and a preoperative MMSE score of ≥ 15 are more likely to maintain independence in the chronic phase.