Author(s): Wick W, Chinot OL, Bendszus M, Mason W, Henriksson R,
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Abstract BACKGROUND: Evaluation of glioblastoma disease status may be complicated by treatment-induced changes and discordance between enhancing and nonenhancing MRI. Exploratory analyses are presented (prospectively assessed pseudoprogression and therapy-related tumor pattern changes) from the AVAglio trial (bevacizumab or placebo plus radiotherapy/temozolomide for newly diagnosed glioblastoma). METHODS: MRI was done every 8 weeks (beginning 4 wk after chemoradiotherapy) using prespecified and standardized T1 and T2 protocols. Progressive disease (PD) at 10 weeks was reconfirmed at 18 weeks to distinguish pseudoprogression. Progression-free survival (PFS), excluding cases of confirmed pseudoprogression, was assessed (post-hoc/exploratory). Tumor progression patterns were determined at each disease assessment/PD (prespecified/exploratory). RESULTS: Of patients with PD in the bevacizumab and placebo arms, 143/354 (40.4\%) and 155/387 (40.1\%), respectively, had PD due to contrast-enhancing lesions, and 51/354 (14.4\%) and 53/387 (13.7\%) had PD due to nonenhancing lesions. Of all patients in the bevacizumab arm (n = 458), 2.2\% had confirmed pseudoprogression versus 9.3\% in the placebo arm (n = 463). Baseline characteristics did not differ between patients with/without pseudoprogression (including for MGMT status). Excluding confirmed pseudoprogression, PFS (hazard ratio: 0.65, 95\% CI: 0.56-0.75; P < .0001, bevacizumab vs placebo) was comparable to the intent-to-treat population. At PD, most patients had the same tumor focus (local/multifocal, >84\%) and infiltrative profile (>88\%) as at baseline; no shift to a diffuse or multifocal phenotype was observed. CONCLUSIONS: Pseudoprogression complicated progression assessment in a small but relevant number of patients but had negligible impact on PFS. Bevacizumab did not appear to adversely impact tumor progression patterns. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: firstname.lastname@example.org.
This article was published in Neuro Oncol
and referenced in Journal of Biomolecular Research & Therapeutics