Glioblastoma growth dynamics: influence in seizure activity and overall survival

Introduction: The prognosis of Glioblastoma (GB) remains dismal. Recent advances in cancer neuroscience have shown that tumors with a high degree of functional connectivity to the rest of the brain have worse prognosis. Furthermore, low velocity of expansion has been linked to increased progression-free survival (PFS) and overall survival (OS) in low-grade glioma. However, it remains unknown whether growth dynamics influence seizure activity and survival of patients with GB. In this study, we sought to investigate whether tumor growth speed has an influence on the emergence of seizure activity and on the survival of patients with GB.

Methods: We conducted a multi-site retrospective review of all patients with a histological diagnosis of GB operated on at three tertiary care academic institutions between January 2005 and January 2021. Patients who underwent two post-operative MRI scans, at least two weeks apart and before adjuvant treatment were included. Growth velocity was deducted from the difference in tumor volume between the two scans. The association between growth velocity and PFS and OS was estimated with a survival function comparing high velocity and low velocity.

Results: A total of 1982 patients were screened, 169 patients fulfilling the criteria were included, and complete imaging data was available for 47 patients. Growth rates ranged from 0.002 cc/day to 1.353 cc/day. Patients with tumors having growth rates >0.1cc/day were not associated with significantly different PFS when compared to patients with tumors having growth rates slower than 0.1cc/day (average 313.25; 264.95; p=0.61). Faster growth rates were significantly associated with higher OS (average 777.88; 522.6; p=0.03). No statistically significant difference was found between growth rates of tumors of patients with seizures when compared to patients not experiencing seizures (average 0.27; 0.18; p=0.81). Similar results were observed for matched cohorts for age and gender.

Conclusion : In this cohort, faster GB growth was associated with higher OS, but not PFS or increased seizure activity. Further prospective validation of these results with higher patient numbers is warranted.