title: Dynamic imaging response following radiation therapy predicts long-term outcomes for diffuse low-grade gliomas.
abstract: Quantitative imaging assessment of radiation therapy (RT) for diffuse low-grade gliomas (DLGG) by measuring the velocity of diametric expansion (VDE) over time has never been studied. We assessed the VDE changes following RT and determined whether this parameter can serve as a prognostic factor. We reviewed a consecutive series of 33 adults with supratentorial DLGG treated with first-line RT with available imaging follow-up (median follow-up, 103 months). Before RT, all patients presented with a spontaneous tumor volume increase (positive VDE, mean 5.9 mm/year). After RT, all patients demonstrated a tumor volume decrease (negative VDE, mean, -16.7 mm/year) during a mean 49-month duration. In univariate analysis, initial tumor volume (>100 cm(3)), lack of IDH1 expression, p53 expression, high proliferation index, and fast post-RT tumor volume decrease (VDE at -10 mm/year or faster, fast responders) were associated with a significantly shorter overall survival (OS). The median OS was significantly longer (120.8 months) for slow responders (post-RT VDE slower than -10.0 mm/year) than for fast responders (47.9 months). In multivariate analysis, fast responders, larger initial tumor volume, lack of IDH1 expression, and p53 expression were independent poor prognostic factors for OS. A high proliferation index was significantly more frequent in the fast responder subgroup than in the slow responder subgroup. We conclude that the pattern of post-RT VDE changes is an independent prognostic factor for DLGG and offers a quantitative parameter to predict long-term outcomes. We propose to monitor individually the post-RT VDE changes using MRI follow-up, with particular attention to fast responders.
authors.affiliation: Department of Neurosurgery, Sainte-Anne Hospital, Paris, France. johanpallud@hotmail.com
authors.forename: Johan
authors.initials: J
authors.lastname: Pallud
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Llitjos
authors.forename: Frédéric
authors.initials: F
authors.lastname: Dhermain
authors.forename: Pascale
authors.initials: P
authors.lastname: Varlet
authors.forename: Edouard
authors.initials: E
authors.lastname: Dezamis
authors.forename: Bertrand
authors.initials: B
authors.lastname: Devaux
authors.forename: Raphaëlle
authors.initials: R
authors.lastname: Souillard-Scémama
authors.forename: Nader
authors.initials: N
authors.lastname: Sanai
authors.forename: Maria
authors.initials: M
authors.lastname: Koziak
authors.forename: Philippe
authors.initials: P
authors.lastname: Page
authors.forename: Michel
authors.initials: M
authors.lastname: Schlienger
authors.forename: Catherine
authors.initials: C
authors.lastname: Daumas-Duport
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Meder
authors.forename: Catherine
authors.initials: C
authors.lastname: Oppenheim
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Roux
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000532:radiotherapy; D018572:Disease-Free Survival; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000473:pathology / Q000532:radiotherapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden