title: Quantitative volumetric analysis of conventional MRI response in recurrent glioblastoma treated with bevacizumab.
abstract: Although the effects of bevacizumab on magnetic resonance images (MRIs) of recurrent glioblastoma multiforme (GBM) are well documented, to our knowledge, no studies have explicitly quantified the volumetric changes resulting from initial treatment, nor have there been studies examining the ability for volumetric changes in conventional MRI to predict progression-free survival (PFS) and overall survival (OS). In the current study, we retrospectively examined volumetric changes on conventional MRI scans in 84 patients with recurrent GBM. MRIs were obtained before (mean, 11 days) and after (mean, 42 days) treatment with bevacizumab. The volume of abnormal fluid-attenuated inversion recovery (FLAIR) signal intensity, the volume of contrast enhancement, and the ratio of the 2 were quantified for each patient before and after initial treatment. Results demonstrated that initial treatment with bevacizumab resulted in a significant decrease in both the volume of abnormal FLAIR signal and the volume of contrast enhancement. Initial, residual, and change in FLAIR volume were not predictive of PFS or OS. Initial contrast-enhancing volume was predictive of PFS but not OS. The pretreatment relative nonenhancing tumor ratio, defined as the ratio of FLAIR to contrast-enhancing volume, was found to be predictive of both PFS and OS.
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA. bellingson@mednet.ucla.edu
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ellingson
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Cloughesy
authors.forename: Albert
authors.initials: A
authors.lastname: Lai
authors.forename: Phioanh L
authors.initials: PL
authors.lastname: Nghiemphu
authors.forename: Paul S
authors.initials: PS
authors.lastname: Mischel
authors.forename: Whitney B
authors.initials: WB
authors.lastname: Pope
mesh_terms: D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D001932:Brain Neoplasms / Q000188:drug therapy*; D018450:Disease Progression; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000188:drug therapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000188:drug therapy*; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab