title: The prognostic value of FET PET at radiotherapy planning in newly diagnosed glioblastoma.
abstract: BACKGROUND
  Glioblastoma patients show a great variability in progression free survival (PFS) and overall survival (OS). To gain additional pretherapeutic information, we explored the potential of O-(2-18F-fluoroethyl)-L-tyrosine (FET) PET as an independent prognostic biomarker.
  
  
  METHODS
  We retrospectively analyzed 146 consecutively treated, newly diagnosed glioblastoma patients. All patients were treated with temozolomide and radiation therapy (RT). CT/MR and FET PET scans were obtained postoperatively for RT planning. We used Cox proportional hazards models with OS and PFS as endpoints, to test the prognostic value of FET PET biological tumor volume (BTV).
  
  
  RESULTS
  Median follow-up time was 14 months, and median OS and PFS were 16.5 and 6.5 months, respectively. In the multivariate analysis, increasing BTV (HR = 1.17, P < 0.001), poor performance status (HR = 2.35, P < 0.001), O(6)-methylguanine-DNA methyltransferase protein status (HR = 1.61, P = 0.024) and higher age (HR = 1.32, P = 0.013) were independent prognostic factors of poor OS. For poor PFS, only increasing BTV (HR = 1.18; P = 0.002) was prognostic. A prognostic index for OS was created based on the identified prognostic factors.
  
  
  CONCLUSIONS
  Large BTV on FET PET is an independent prognostic factor of poor OS and PFS in glioblastoma patients. With the introduction of FET PET, we obtain a prognostic index that can help in glioblastoma treatment planning.
authors.affiliation: Department of Radiation Biology, The Finsen Center, Rigshospitalet, Section 6321, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark. sidsel.hoejklint.poulsen@regionh.dk.|Department of Clinical Physiology, Nuclear Medicine and PET, Center of Diagnostic Investigation, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark. sidsel.hoejklint.poulsen@regionh.dk.
authors.forename: Sidsel Højklint
authors.initials: SH
authors.lastname: Poulsen
authors.affiliation: Department of Radiation Biology, The Finsen Center, Rigshospitalet, Section 6321, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.|Department of Oncology, The Finsen Center, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Urup
authors.affiliation: Department of Radiation Biology, The Finsen Center, Rigshospitalet, Section 6321, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.|Department of Oncology, The Finsen Center, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Grunnet
authors.affiliation: Laboratory of Gastroenterology, University of Copenhagen, Hvidovre Hospital, Kettegård Allé 30, DK-2650, Copenhagen, Denmark.
authors.forename: Ib Jarle
authors.initials: IJ
authors.lastname: Christensen
authors.affiliation: Department of Radiology, Center of Diagnostic Investigation, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
authors.forename: Vibeke Andrée
authors.initials: VA
authors.lastname: Larsen
authors.affiliation: Department of Oncology, The Finsen Center, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.|Section of Radiotherapy, The Finsen Center, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
authors.forename: Michael Lundemann
authors.initials: ML
authors.lastname: Jensen
authors.affiliation: Department of Oncology, The Finsen Center, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.|Section of Radiotherapy, The Finsen Center, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
authors.forename: Per Munck
authors.initials: PM
authors.lastname: Af Rosenschöld
authors.affiliation: Department of Radiation Biology, The Finsen Center, Rigshospitalet, Section 6321, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.|Department of Oncology, The Finsen Center, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
authors.forename: Hans Skovgaard
authors.initials: HS
authors.lastname: Poulsen
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Center of Diagnostic Investigation, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
authors.forename: Ian
authors.initials: I
authors.lastname: Law
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed; D014443:Tyrosine / Q000031:analogs & derivatives*
chemical_list: C117289:O-(2-fluoroethyl)tyrosine; D019275:Radiopharmaceuticals; D014443:Tyrosine
keywords: Biomarker; FET PET; Glioblastoma; Prognostic index; Radiation therapy