title: Use of (11)C-methionine PET parametric response map for monitoring WT1 immunotherapy response in recurrent malignant glioma.
abstract: OBJECTIVE
  Immunotherapy targeting the Wilms tumor 1 (WT1) gene product is a promising treatment modality for patients with malignant gliomas, and there have been reports of encouraging results. It has become clear, however, that Gd-enhanced MR imaging does not reflect prognosis, thereby necessitating a more robust imaging evaluation system for monitoring response to WT1 immunotherapy. To meet this demand, the authors performed a voxel-wise parametric response map (PRM) analysis of (11)C-methionine PET (MET-PET) in WT1 immunotherapy and compared the data with the overall survival after initiation of WT1 immunotherapy (OS(WT1)).
  
  
  METHODS
  Fourteen patients with recurrent malignant glioma were included in the study, and OS(WT1) was compared with: 1) volume and length change in the contrast area of the tumor on Gd-enhanced MR images; 2) change in maximum uptake of (11)C-methionine; and 3) a more detailed voxel-wise PRM analysis of MET-PET pre- and post-WT1 immunotherapy.
  
  
  RESULTS
  The PRM analysis was able to identify the following 3 areas within the tumor core: 1) area with no change in (11)C-methionine uptake pre- and posttreatment; 2) area with increased (11)C-methionine uptake posttreatment (PRM(+MET)); and 3) area with decreased (11)C-methionine uptake posttreatment. While the results of Gd-enhanced MR imaging volumetric and conventional MET-PET analysis did not correlate with OS(WT1) (p = 0.270 for Gd-enhanced MR imaging length, p = 0.960 for Gd-enhanced MR imaging volume, and p = 0.110 for MET-PET), the percentage of PRM(+MET) area showed excellent correlation (p = 0.008) with OS(WT1).
  
  
  CONCLUSIONS
  This study describes the limited value of Gd-enhanced MR imaging and highlights the potential of voxel-wise PRM analysis of MET-PET for monitoring treatment response in immunotherapy for malignant gliomas. Clinical trial registration no.: UMIN000002001.
authors.affiliation: Departments of Neurosurgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Chiba
authors.forename: Manabu
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Okita
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tsuboi
authors.forename: Kayako
authors.initials: K
authors.lastname: Isohashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Kagawa
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Fujimoto
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Oji
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Oka
authors.forename: Eku
authors.initials: E
authors.lastname: Shimosegawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morita
authors.forename: Jun
authors.initials: J
authors.lastname: Hatazawa
authors.forename: Haruo
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Naoya
authors.initials: N
authors.lastname: Hashimoto
authors.forename: Toshiki
authors.initials: T
authors.lastname: Yoshimine
mesh_terms: D000276:Adjuvants, Immunologic; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D019496:Cancer Vaccines / Q000008:administration & dosage*; D002250:Carbon Radioisotopes; D002470:Cell Survival / Q000187:drug effects* / Q000235:genetics; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007271:Injections, Intradermal; D008279:Magnetic Resonance Imaging; D008297:Male; D008353:Mannitol / Q000031:analogs & derivatives; D008715:Methionine; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D009829:Oleic Acids; D049268:Positron-Emission Tomography / Q000379:methods*; D011849:Radioactive Tracers; D047368:Tumor Burden / Q000187:drug effects; D025721:WT1 Proteins / Q000187:drug effects*; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D019496:Cancer Vaccines; D002250:Carbon Radioisotopes; D009829:Oleic Acids; D011849:Radioactive Tracers; D025721:WT1 Proteins; C477385:montanide ISA 51; D008353:Mannitol; D008715:Methionine