gms | German Medical Science

Objective: Glioblastoma (GBM) show variable presentation on magnetic resonance imaging (MRI), whereas in approximately 20% of the cases a multilocular spread is found (mGBM). The consideration of FLAIR (fluid-inversion-recovery)-sequence in the assessment of GBM facilitates a better evaluation of mGBM. A significantly worse survival of mGBM has been reported compared to patients with solitary GBM and the management of these patients remains challenging. The aim of this study was to evaluate clinical, imaging and molecular predictors of outcome in mGBM, that could be supportive in the treatment decision-making process in this patient population.

Methods: We performed a retrospective analysis of GBM-patients treated between 2008 and 2018. mGBM were defined as multiple tumor lesions in T1-eanhanced and FLAIR-sequence of MRI. Overall survival (OS) was calculated from the date of diagnosis to the date of death. The extent of resection (EoR) and the adjuvant treatment regime were documented. Imaging criteria as well as molecular markers (MGMT, IDH1, p53, Ki67) were analyzed using Python 3.7 (Python Software Foundation). Survival analysis was done using Kaplan-Meier curve and significance was determined by the log-rank test. Significant factors affecting survival were then processed in multivariate analysis using Cox’s regression test. A p-value <0.05 was considered significant.

Results: A total of 45 patients with mGBM were included. The mean age was 64.1 years (range 36-89), 64.4% (29/45) were male and 35.6% (16/45) were female. The achieved EoR was as followed: biopsy in 66.7% (30/45), and GTR in 33.3% (15/45). R-CH (Stupp) was performed in 86.7% (39/45). The mean OS was 13.87 months (range 1-104). Significant predictors of OS were age (r=-0.43, p=0.003) and Karnofsky Performance Status (KPS) before treatment (r=0.3, p=0.05). There was no significant correlation of imaging or molecular parameter with OS. We found no significant difference in OS between biopsied mGBM and mGBM with GTR.

Conclusion: The survival of patients with mGBM remains poor, whereas only younger age and a better clinical condition at presentation were associated with longer OS. The EoR had no positive influence on survival, which does not justify a surgical indication to resect multiple lesions in patients with mGBM. Therefore, GTR should not be considered as a treatment option in this patient population. An explanation for these findings might be a more advanced tumor expansion in mGBM-patients affecting the whole brain in contrast to solitary GBM.