Impact of EGFR A289T/V mutation on relapse pattern in glioblastoma.

Background: Molecular factors influence relapse patterns in glioblastoma. The hotspot mutation located at position 289 of the extracellular domain of the epidermal growth factor receptor (EGFR ^A289mut ) is associated with a more infiltrative phenotype. The primary objective of this study was to explore the impact of the EGFR ^A289 mutation on the pattern of relapse after chemoradiotherapy-based treatment of patients suffering from newly diagnosed glioblastoma.
Patients and Methods: An ancillary study from a prospective cohort of patients suffering from glioblastoma was conducted. All patients received radiotherapy and concomitant temozolomide. The population was divided into two groups according to EGFR ^A289 status (mutated versus wild-type). The primary endpoint was the overlap score (varying from 0 to 1) between the initial irradiated tumor volume (Vinit) and the relapse volume (Vr). Secondary endpoints explored the impact of EGFR ^A289mut on survival.
Results: One hundred twenty-eight patients were included and analyzed: 11% had EGFR ^A289mut glioblastoma (n = 14/128). EGFR ^A289mut glioblastomas had a relapse pattern that was more marginal than EGFR ^A289wt glioblastomas: a median overlap score Vinit/Vr of 0.96 was observed in the EGFR ^A289mut group versus 1 in the EGFR ^A289wt group (P = 0.05). Half of the population with EGFR ^A289mut tumor (n = 7/14) had a marginal relapse (i.e. overlap score ^Vr/Vinit ≤ 0.95) compared to 23.7% (n = 27/114) in the EGFR ^A289wt group, P = 0.035. EGFR ^A289mut did not influence survival.
Conclusion: We highlighted a link between the EGFR ^A289 mutation and the relapse pattern in glioblastoma. The independent role of EGFR ^A289mut and its clinical implication should now be explored in further studies.
(Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)