title: Recurrence pattern analysis after re-irradiation with bevacizumab in recurrent malignant glioma patients.
abstract: BACKGROUND
  The aim of the present analysis was to evaluate the recurrence pattern in patients with recurrent malignant glioma after re-irradiation in combination with bevacizumab as there is limited data on how to optimally choose dose, fractionation and delineation margins.
  
  
  METHODS
  Thirty-one patients with recurrent malignant glioma treated with re-irradiation and bevacizumab after previous chemoradiotherapy (concurrent temozolomide 75 mg/m(2)/d according to the EORTC/NCIC trial) and [(18) F]FET-PET and/or MRI confirmed recurrence were retrospectively analyzed. Bevacizumab was applied twice during fractionated re-irradiation (10 mg/kg, d1+d15, median 36 Gy, conventionally fractionated). Recurrence patterns were assessed by means of [(18) F]FET-PET and/or MRI.
  
  
  RESULTS
  Median follow-up was 34.0 months for all patients [95%-CI, 27.7-40.3] and median post-recurrence survival 10.8 months [95%-CI, 9.2-12.4]. Concerning the recurrence patterns, 61.3% of these were located in-field (19 patients), 22.6% were marginal (7 patients) and 16.1% ex-field (5 patients). No influence on the recurrence pattern was observed according to sex, WHO grade, maintenance chemotherapy or MGMT methylation status whereas planning target volume (PTV) size had a significant influence on the recurrence pattern (p=0.032). PTV sizes>75 ml were associated with a higher in-field recurrence rate and lower median post-recurrence progression-free survival (8.5 vs. 4.9 months, p=0.016).
  
  
  CONCLUSIONS
  After the administration of re-irradiation with bevacizumab the recurrence pattern seems to be mainly centrally located. The PTV size was the main predictor for a marginal/ex-field recurrence.
authors.affiliation: Department of Radiation Oncology, University Hospital of Munich, Marchioninistr. 15, 81377, Munich, Germany. maximilian.niyazi@med.uni-muenchen.de.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Niyazi
authors.affiliation: Department of Nuclear Medicine, University of Munich, Marchioninistr. 15, 81377, Munich, Germany. Nathalie.Jansen@med.uni-muenchen.de.
authors.forename: Nathalie Lisa
authors.initials: NL
authors.lastname: Jansen
authors.affiliation: Department of Radiation Oncology, University Hospital of Munich, Marchioninistr. 15, 81377, Munich, Germany. Maya.Rottler@med.uni-muenchen.de.
authors.forename: Maya
authors.initials: M
authors.lastname: Rottler
authors.affiliation: Department of Radiation Oncology, University Hospital of Munich, Marchioninistr. 15, 81377, Munich, Germany. Ute.Ganswindt@med.uni-muenchen.de.
authors.forename: Ute
authors.initials: U
authors.lastname: Ganswindt
authors.affiliation: Department of Radiation Oncology, University Hospital of Munich, Marchioninistr. 15, 81377, Munich, Germany. Claus.Belka@med.uni-muenchen.de.
authors.forename: Claus
authors.initials: C
authors.lastname: Belka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage; D000068258:Bevacizumab / Q000008:administration & dosage; D001932:Brain Neoplasms / Q000473:pathology* / Q000628:therapy; D059248:Chemoradiotherapy / Q000379:methods*; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D005910:Glioma / Q000473:pathology* / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D000068258:Bevacizumab