Survival of patients with glioblastoma - advancements in the past two decades

Abstract

Background: Glioblastoma is the most common and most aggressive form of primary malignant brain tumors in adults. The prognosis is generally poor, with a median survival of around 15-16 months, even with aggressive multimodal treatment. Aim: The overall goal of this thesis is to investigate prognostic factors and clinical outcomes in patients with glioblastoma in a population-based setting. Methods: Study I is a retrospective study including 229 patients with glioblastoma who underwent surgery at Sahlgrenska University Hospital between January 2004 and December 2008. In Study II and III, patients were enrolled prospectively at the same hospital between November 2012 and June 2016. A total of 222 patients with glioblastoma who underwent surgery were included in Study II, and a total of 131 patients with radiologically suspected glioblastoma who did not undergo surgery were included in Study III. For Study I-III, patient-, tumor-, and treatment-related characteristics were collected from patient medical records. In Study I and II, Poisson regression models were used for the analyses of possible prognostic factors and their relation to survival, while in Study III, statistical analyses were performed using IBM SPSS Statistics. Study IV is a methodological study describing the methods and design of several studies that use a shared research database at Sahlgrenska University Hospital. Results: In Study I, median survival was 8.8 months, and the independent prognostic factors for longer survival were younger age, secondary tumor genesis, unifocal tumor location, tumor resection, radiotherapy, and radiotherapy plus chemotherapy. In study II, median survival was 12.8 months, and factors associated with longer survival in the multivariable model were MGMT promoter hypermethylation, non-central tumor location, complete resection of contrast-enhancing tumor, WHO performance status 0-1, unilateral tumor location, tumor spread in one lobe only, and no comorbidity. In Study III of elderly, non-operated patients with poorer performance status, the median survival was 3.6 months, however, the subgroup that received oncological treatment despite lack of histological diagnosis had a longer median survival of 6.8 months. Conclusions: Survival for patients who underwent surgery for glioblastoma has significantly increased over time, while a greater proportion of patients underwent surgery and received adjuvant oncological treatment. A subgroup of patients with suspected glioblastoma who did not undergo surgery but received oncological treatment had clinical benefit from treatment with temozolomide.