title: Patterns of failure after radiotherapy for pediatric patients with intracranial ependymoma.
abstract: To investigate the patterns of failure after radiotherapy for pediatric intracranial ependymoma and their correlation with dose parameters.
  
  
  
  Between 2000 and 2013, 206 patients were treated in France. MRI scans at relapse were registered to the original planning CTs for topographic analysis of failure patterns. To compare relapse patients (RP) with non relapse patients (NRP), several dose parameters were derived from dose volume histograms.
  
  
  
  Over a median follow-up of 53.8months, 84 patients presented with relapse. Topographic analysis showed 50 patients with local relapse in the radiation field, 6 in the edge of field, 6 locoregional outside the field, 10 in the spine, 5 supratentorial and 7 local and distant. The median coverage, target coverage and homogeneity indices did not differ significantly between RP and NRP. The median volume of in-field relapse was 1.25cc [0.11, 27], with a median dose of 57.83Gy [50.04, 61.69].
  
  
  
  Local relapse in the tumor bed and the higher dose regions was the predominant pattern of failure. Improving coverage of the target volume and increasing the dose to the high radioresistant regions, taking into consideration other clinical and biological pronostic factors, may be an effective way of reducing local failures.
authors.affiliation: Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France. Electronic address: fatima.tensaouti@inserm.fr.
authors.forename: Fatima
authors.initials: F
authors.lastname: Tensaouti
authors.affiliation: Department of Radiation Oncology, Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse - Oncopole, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Ducassou
authors.affiliation: Department of Biostatistics, Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse - Oncopole, France.
authors.forename: Léonor
authors.initials: L
authors.lastname: Chaltiel
authors.affiliation: Department of Radiation Oncology, Institut Gustave Roussy, Paris, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Bolle
authors.affiliation: Department of Radiation Oncology, CHU La Timone, Marseille, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Muracciole
authors.affiliation: Department of Radiation Oncology, Centre Oscar Lambret, Lille, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Coche-Dequeant
authors.affiliation: Department of Radiation Oncology, Institut Curie, Paris, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Alapetite
authors.affiliation: Department of Radiation Oncology, Centre Alexis Vautrin, Vandoeuvre, Nancy, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Bernier
authors.affiliation: Department of Radiation Oncology, Centre Léon Bérard, Lyon, France.
authors.forename: Line
authors.initials: L
authors.lastname: Claude
authors.affiliation: Department of Radiation Oncology, Institut de cancérologie de l'ouest, Nantes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Supiot
authors.affiliation: Department of Radiation Oncology, CHU Bordeaux, France.
authors.forename: Aymeri
authors.initials: A
authors.lastname: Huchet
authors.affiliation: Department of Radiation Oncology, Institut régional du Cancer Montpellier-Val d'Aurelle, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Kerr
authors.affiliation: Department of Radiation Oncology, Centre Eugène Marquis, Rennes, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: le Prisé
authors.affiliation: Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France; Department of Radiation Oncology, Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse - Oncopole, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Laprie
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D004806:Ependymoma / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D005602:France; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D011879:Radiotherapy Dosage; D017211:Treatment Failure
keywords: Dose; Ependymoma; Intracranial; Radiotherapy; Relapse failure