title: Patterns of failure for patients with glioblastoma following O-(2-[18F]fluoroethyl)-L-tyrosine PET- and MRI-guided radiotherapy.
abstract: To evaluate the patterns of failure following clinical introduction of amino-acid O-(2-[18F]fluoroethyl)-L-tyrosine (FET)-PET-guided target definition for radiotherapy (RT) of glioblastoma patients.
  
  
  
  The first 66 consecutive patients with confirmed histology, scanned using FET-PET/CT and MRI were selected for evaluation. Chemo-radiotherapy was delivered to a volume based on both MRI and FET-PET (PETvol). The volume of recurrence (RV) was defined on MRI data collected at the time of progression according to RANO criteria.
  
  
  
  Fifty patients were evaluable, with median follow-up of 45months. Central, in-field, marginal and distant recurrences were observed for 82%, 10%, 2%, and 6% of the patients, respectively. We found a volumetric overlap of 26%, 31% and 39% of the RV with the contrast-enhancing MR volume, PETvoland the composite MRPETvol, respectively. MGMT-methylation (p=0.03), larger PETvol(p<0.001), and less extensive surgery (p<0.001), were associated with larger PETvoloverlap.
  
  
  
  The combined MRPETvolhad a stronger association with the recurrence volume than either of the modalities alone. Larger overlap of PETvoland RV was observed for patients with MGMT-methylation, less extensive surgery, and large PETvolon the RT-planning scans.
authors.affiliation: Department of Oncology, Section of Radiotherapy, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark; Niels Bohr Institute, Department of Science, University of Copenhagen, København Ø, Denmark. Electronic address: michael.lundemann.jensen@regionh.dk.
authors.forename: Michael
authors.initials: M
authors.lastname: Lundemann
authors.affiliation: Department of Oncology, Section of Radiotherapy, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark; Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark.
authors.forename: Junia Cardoso
authors.initials: JC
authors.lastname: Costa
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark.
authors.forename: Ian
authors.initials: I
authors.lastname: Law
authors.affiliation: Department of Oncology, Section of Radiotherapy, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark.
authors.forename: Svend Aage
authors.initials: SA
authors.lastname: Engelholm
authors.affiliation: Department of Oncology, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark.
authors.forename: Aida
authors.initials: A
authors.lastname: Muhic
authors.affiliation: Department of Oncology, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark.
authors.forename: Hans Skovgaard
authors.initials: HS
authors.lastname: Poulsen
authors.affiliation: Department of Oncology, Section of Radiotherapy, Rigshospitalet, Copenhagen University Hospital, København Ø, Denmark; Niels Bohr Institute, Department of Science, University of Copenhagen, København Ø, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Munck Af Rosenschold
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000532:radiotherapy*; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D015642:Radiology, Interventional / Q000379:methods; D019275:Radiopharmaceuticals; D061089:Radiotherapy, Image-Guided / Q000379:methods; D012189:Retrospective Studies; D017211:Treatment Failure; D014443:Tyrosine / Q000031:analogs & derivatives*
chemical_list: C117289:O-(2-fluoroethyl)tyrosine; D019275:Radiopharmaceuticals; D014443:Tyrosine
keywords: FET-PET; Glioma; MRI; Radiotherapy; Recurrence patterns