Age alone is not a predictor for survival in glioblastoma

Abstract

Over half of glioblastoma (GBM) cases are diagnosed in patients older than 65years. Their median overall survival (OS) is 4-5months, compared with 12-14months in patients younger than 70years. This retrospective audit aims to identify patterns of care and survival of patients diagnosed with GBM at a single institution in Melbourne, Australia. Consecutive histological diagnoses of adult primary GBM from January 2010 to December 2012 were retrospectively identified from medical records. Demographic, treatment and survival characteristics were recorded until death, with follow-up to January 1st 2015. Survival was estimated by Kaplan-Meier method. Planned, sub-group analyses were conducted using multivariate Cox proportional hazards model to identify differences between elderly and younger cohorts, as well as ECOG. 165 patients were identified (36 % aged ≥70years). Those ≥70years had a poorer performance status (ECOG 3-4: 27 vs 10 %, p = .005); poorer median OS (2.6 vs 11.5months, p < .001); and were less likely to receive adjuvant treatment (no treatment: 40 vs 16 %, p < .001) compared with patients <70years. Age was not a significant predictor of poorer os (HR 1.0; 0.99-1.03; p > .05), after adjusting for other clinical factors. Significant predictors of poorer os were poor performance status (p = .001), bilateral tumours (p = .04), biopsy only (p = .001), and no adjuvant treatment (p < .001). In patients diagnosed with GBM, those older than 70years often present with poor performance status, are less likely to receive adjuvant treatment and have inferior os compared with younger patients. Treatment recommendations should be based on performance status/fitness, not age alone.