title: Panel review of anaplastic oligodendroglioma from European Organization For Research and Treatment of Cancer Trial 26951: assessment of consensus in diagnosis, influence of 1p/19q loss, and correlations with outcome.
abstract: The diagnosis of anaplastic oligodendroglioma (AOD) or anaplastic oligoastrocytoma (AOA) is subject to interobserver variation. The aim of this study was to estimate consensus in typing and grading of these tumors using tumor material collected in a large prospective randomized phase III study and to correlate the consensus diagnosis with the 1p/19q status of the tumors and the clinical outcome. The available pathology material of the first 150 patients, randomized into the European Organization for Research and Treatment of Cancer Trial 26951, was reviewed by an independent panel of 9 neuropathologists. The presence of deletions of 1p and 19q was assessed by fluorescence in situ hybridization with locus-specific probes. The panel reached consensus on the diagnosis of AOD in 52% of the tumors that had been diagnosed as AOD by the local pathologists, whereas only 8% of the local diagnosis of AOA was confirmed with consensus. The concordance on the panel diagnosis of AOD was high (intraclass correlation = 86%). The survival curves for AOD with 1p/19q loss, AOD without these losses, and AOA without 1p/19q loss ran separately in this order. The absence of necrosis and the presence of endothelial abnormalities were correlated with better outcomes. In multivariate analysis, patients' age, 1p/19q loss, and necrosis were identified as independent prognostic factors.
authors.affiliation: Department of Pathology, Erasmus Medical Center, Rotterdam, The Netherlands. j.m.kros@erasmusmc.nl
authors.forename: Johan M
authors.initials: JM
authors.lastname: Kros
authors.forename: Thierry
authors.initials: T
authors.lastname: Gorlia
authors.forename: Mathilde C
authors.initials: MC
authors.lastname: Kouwenhoven
authors.forename: Ping-Pin
authors.initials: PP
authors.lastname: Zheng
authors.forename: V Peter
authors.initials: VP
authors.lastname: Collins
authors.forename: Dominique
authors.initials: D
authors.lastname: Figarella-Branger
authors.forename: Felice
authors.initials: F
authors.lastname: Giangaspero
authors.forename: Caterina
authors.initials: C
authors.lastname: Giannini
authors.forename: Karima
authors.initials: K
authors.lastname: Mokhtari
authors.forename: Sverre J
authors.initials: SJ
authors.lastname: Mørk
authors.forename: Anders
authors.initials: A
authors.lastname: Paetau
authors.forename: Guido
authors.initials: G
authors.lastname: Reifenberger
authors.forename: Martin J
authors.initials: MJ
authors.lastname: van den Bent
mesh_terms: D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology*; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics*; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015588:Observer Variation; D009837:Oligodendroglioma / Q000235:genetics* / Q000473:pathology*; D011379:Prognosis; D011446:Prospective Studies; D016019:Survival Analysis