Functional connectivity within glioblastoma impacts overall survival.

BACKGROUND Glioblastoma (GBM; WHO grade IV) assumes a variable appearance on magnetic resonance imaging owing to heterogeneous proliferation and infiltration of its cells. As a result, the neurovascular units responsible for functional connectivity (FC) may exist within gross tumor boundaries, albeit with altered magnitude. Therefore, we hypothesize that the strength of functional connectivity within GBMs is predictive of overall survival. METHODS We used pre-defined FC regions of interest (ROIs) in denovo GBM patients to characterize the presence of within-tumor FC observable via resting-state fMRI and its relationship to survival outcomes. RESULTS 57 GBM patients (mean age 57.8 ± 13.9 years) were analyzed. Functionally connected voxels, not identifiable on conventional structural images, can be routinely found within the tumor mass and was not significantly correlated to tumor size. In patients with known survival times (n = 31), higher intra-network FC strength within GBM tumors was associated with better overall survival even after accounting for clinical and demographic covariates. CONCLUSIONS These findings suggest the possibility that functionally intact regions may persist within GBMs and that the extent to which FC is maintained may carry prognostic value and inform treatment planning.