The prognostic significance of midline shift at presentation on survival in patients with glioblastoma multiforme

Purpose: While patients with glioblastoma multiforme (GBM) who present with midline shift have a presumably worse prognosis, there is little literature evaluating the prognostic significance of this presentation in multivariate analysis in the context of other known prognostic factors. Methods and Materials: From March 1981 to September 1993, 219 patients underwent irradiation for intracranial glioma at our institution. One hundred fourteen patients with a diagnosis of a primary GBM were analyzed for the influence of the presence of midline shift at diagnosis on survival with respect to other known prognostic factors, including age, Karnofsky performance status (KPS), and extent of surgery. Eighty-five patients (74%) presented with midline shift. Surgical treatment consisted of subtotal/total resection in 86 patients (75%). Among patients presenting with midline shift, 68 (80%) underwent subtotal/total resection before irradiation. Results: Multivariate analysis of the entire cohort of patients found none of the potential prognostic factors analyzed to significantly influence survival. The overall median survival was 6 months. However, when multivariate analysis was limited to patients with a KPS of ≥ 70, only the presence of midline shift and age were found to significantly influence survival. Patients with a KPS ≥ 70 and with midline shift present at diagnosis had a median survival of 8 months, as compared to 14 months for those not having midline shift at presentation ( p = 0.04). Patients with a KPS ≥ 70 and age > 50 years had a median survival of 5 months as compared to 11 months for those ≤ 50 ( p = 0.02). Conclusion: In this series, where 80% of patients who presented with a midline shift underwent decompressive resection of GBM before irradiation, the presence of midline shift at diagnosis remained an independent prognostic factor influencing survival among good performance status patients. While the role of decompressive surgery in this setting is likely of some benefit, the extent of this benefit remains to be defined.