The Shifting Prognostic Value of Performance Status in Aging Glioblastoma Patients: A Retrospective Cohort Study

To evaluate how advancing age affects the prognostic value of preoperative versus postoperative Karnofsky Performance Status (KPS) for guiding clinical interventions in glioblastoma (GBM) patients aged 60 and older.

This retrospective cohort study included 89 patients (≥60 years) with newly diagnosed GBM treated between 2017 and 2021. We analyzed demographic, clinical, and treatment data, identifying prognostic factors for overall survival (OS) via Cox proportional hazards models. The utility of preoperative and postoperative KPS was assessed in age-stratified subgroups (60-64, 65-69, and ≥70 years) using Kaplan-Meier analysis.

Multivariable analysis confirmed greater extent of resection (P<0.001), higher postoperative KPS (HR: 0.981, P=0.006), and chemoradiation (P<0.001) as independent predictors of improved OS. Age-stratified analysis revealed that preoperative KPS was prognostic only in the "young-elderly" group (60-64 years, P=0.003), losing its predictive power in patients aged ≥65. In contrast, postoperative KPS remained a robust and consistent prognostic indicator across all elderly age groups (P≤0.001 for all).

The prognostic utility of preoperative KPS diminishes significantly after age 65, suggesting its use as a standalone determinant for aggressive interventions should be reconsidered in the older-elderly. Postoperative KPS, however, is a powerful predictor across the aging spectrum. These clinical-only findings underscore that interventions preserving functional status are critical to improving outcomes in this aging population.