Introduction: Glioblastoma (GB) is the most common and aggressive type of primary brain tumor in adults. Average survival is approximately one year, but individual survival is heterogeneous. Using a single institutional experience, we have previously identified pre-operative factors associated with survival and devised a prognostic scoring system based on these factors. The aims of the present study are to validate these pre-operative factors and verify the efficacy of this scoring system using a multi-institutional cohort.

Methods: Adult patient who underwent first-time surgery for an intracranial GB at three academic tertiary-care institutions between 2007-2010 were retrospectively reviewed. Multivariate proportional hazards regression analysis was used to identify pre-operative factors associated with survival. Survival as a function of time was plotted using the Kaplan-Meier method, and survival rates were compared using Log-rank analysis.

Results: Of the 334 patients in this study, the pre-operative factors found to be negatively associated with survival were: age>60 years (p<0.0001), KPS=80 (p=0.03), motor deficit (p=0.02), language deficit (p=0.04), and periventricular tumor location (p=0.04). Patients possessing 0-1, 2, 3, and 4-5 of these variables were assigned a pre-operative grade of 1, 2, 3, and 4, respectively. Patients with a pre-operative grade of 1, 2, 3, and 4 had a median survival of 17.9, 12.3, 10, and 7.5 months. Survival of each of these grades was statistically significant (p<0.05).

Conclusions: This grading system, based only on pre-operative variables, may provide patients and physicians with prognostic information that may guide medical and surgical therapy before any intervention is pursued.

Patient Care: The factors and classification system validated by this study may provide patients and physicians with prognostic information that may guide medical and surgical therapy. These can be employed before any treatments are pursued.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of pre-operative factors in prognosticating survival for patients with GB, 2) Discuss, in small groups, the relevance of these factors in guiding treatment strategies, and 3) Identify clinical factors that may prognosticate survival for patients with GB.

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