title: Treatment response evaluation using 18F-FDOPA PET in patients with recurrent malignant glioma on bevacizumab therapy.
abstract: OBJECTIVE
  This study compares the value of 3,4-dihydroxy-6-[(18)F]-fluoro-l-phenylalanine ((18)F-FDOPA) positron emission tomography (PET) and MRI in assessing outcome during antiangiogenic treatment in patients with recurrent high-grade gliomas.
  
  
  METHODS
  Thirty patients were prospectively studied with (18)F-FDOPA PET scans immediately before, and two and six weeks after start of bevacizumab therapy. (18)F-FDOPA metabolic tumor volumes (MTV) as well as max and mean standardized uptake values (SUV) within this MTV were obtained. MRI treatment response was assessed at six weeks. The predictive ability of (18)F-FDOPA PET and MRI response assessment were evaluated with regard to progression-free survival (PFS) and overall survival (OS).
  
  
  RESULTS
  A total of 30, 28, and 24 (18)F-FDOPA PET scans at baseline, two weeks, and six weeks, were available for analysis, respectively. (18)F-FDOPA PET SUVs as well as their changes through therapy were not predictive of outcome. However, MTV parameters such as MTV changes were highly prognostic. Interestingly, absolute MTV at the first follow up scan provides the most significant prediction for increased OS (P < 0.0001) as well as PFS (P = 0.001). This surprising result was scrutinized with cross-validation and simulation analysis. Responders based on (18)F-FDOPA PET data survived 3.5 times longer (12.1 months vs. 3.5 months, median OS, P < 0.001) than nonresponders (17 patients vs. 11 patients, respectively). In comparison, responders based on MRI data lived 1.5 times longer (11.4 months vs 7.7 months, P = 0.03) than nonresponders (22 patients vs. 7 patients, respectively).
  
  
  CONCLUSIONS
  (18)F-FDOPA PET identifies treatment responders to antiangiogenic therapy as early as two weeks after treatment initiation.
authors.affiliation: Authors' Affiliations: Department of Molecular and Medical Pharmacology; Ahmanson Translational Imaging Division; Departments of Department of Pediatric and Adolescent Medicine, Medical University of Vienna, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Schwarzenberg
authors.affiliation: Authors' Affiliations: Department of Molecular and Medical Pharmacology; Ahmanson Translational Imaging Division; Departments of.
authors.forename: Johannes
authors.initials: J
authors.lastname: Czernin
authors.affiliation: Neurology.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Cloughesy
authors.affiliation: Diagnostic Imaging, and.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ellingson
authors.affiliation: Diagnostic Imaging, and.
authors.forename: Whitney B
authors.initials: WB
authors.lastname: Pope
authors.affiliation: Medicine Statistics Core, University of California, Los Angeles; and.
authors.forename: Tristan
authors.initials: T
authors.lastname: Grogan
authors.affiliation: Medicine Statistics Core, University of California, Los Angeles; and.
authors.forename: David
authors.initials: D
authors.lastname: Elashoff
authors.affiliation: Authors' Affiliations: Department of Molecular and Medical Pharmacology; Ahmanson Translational Imaging Division; Departments of.
authors.forename: Cheri
authors.initials: C
authors.lastname: Geist
authors.affiliation: Authors' Affiliations: Department of Molecular and Medical Pharmacology; Ahmanson Translational Imaging Division; Departments of.
authors.forename: Daniel H S
authors.initials: DH
authors.lastname: Silverman
authors.affiliation: Authors' Affiliations: Department of Molecular and Medical Pharmacology;
authors.forename: Michael E
authors.initials: ME
authors.lastname: Phelps
authors.affiliation: Authors' Affiliations: Department of Molecular and Medical Pharmacology; Ahmanson Translational Imaging Division; Departments of weichen@mednet.ucla.edu.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D000068258:Bevacizumab; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000188:drug therapy* / Q000401:mortality; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000378:metabolism; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000188:drug therapy* / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D049268:Positron-Emission Tomography; D011379:Prognosis; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; C043437:fluorodopa F 18; D000068258:Bevacizumab; D004295:Dihydroxyphenylalanine