title: Performance of FDG PET/CT in postoperative colorectal cancer patients with a suspected recurrence and a normal CEA level.
abstract: OBJECTIVE
  The performance of 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) has been not established for the evaluation of recurrent colorectal cancer. The aim of this study was to evaluate the diagnostic value of FDG PET/CT in postoperative colorectal cancer patients with normal carcinoembryonic antigen (CEA) levels.
  
  
  METHODS
  This retrospective study was conducted on 63 FDG PET/CT cases, involving postoperative colorectal cancer patients suspected of having recurrent or metastatic lesions with normal CEA levels. The diagnostic performance of FDG PET/CT was evaluated based on diverse suspected conditions, using physical examination, a conventional imaging work-up, and endoscopy. Histopathology, a clinical imaging work-up (including an FDG PET/CT examination), and determination of tumor marker levels during the follow-up served as the reference standard.
  
  
  RESULTS
  The sensitivity, specificity, and accuracy for FDG PET/CT were 95, 76.6, and 88.8% for a lesion-by-lesion analysis, and 96.3, 86.1, and 90.5% for a case-by-case analysis, respectively. Three false-negative lesions among 107 suspected recurrent findings were identified as compared with nine false-positive lesions. For radiologically suspected recurrent or metastatic conditions, FDG PET/CT diagnostic performance was superior to radiological image modalities, for both lesion-by-lesion and case-by-case analyses. On follow-up of patients with normal CEA levels, but high CA19-9 levels, the use of FDG PET/CT detected true-positive findings in 63.3% of cases.
  
  
  CONCLUSIONS
  FDG PET/CT is a valuable tool to distinguish recurrence or metachronous tumor from postoperative changes or other benign lesions in postoperative colorectal cancer patients with normal CEA levels and radiologically or clinically suspicious lesions.
authors.affiliation: Department of Nuclear Medicine, Dankook University College of Medicine, Cheonan, Korea. jaihyuenlee@dankook.ac.kr
authors.forename: Jai Hyuen
authors.initials: JH
authors.lastname: Lee
authors.forename: Seok Gun
authors.initials: SG
authors.lastname: Park
authors.forename: Keum Nahn
authors.initials: KN
authors.lastname: Jee
authors.forename: Dong Guk
authors.initials: DG
authors.lastname: Park
authors.forename: Hwan
authors.initials: H
authors.lastname: Namgung
authors.forename: Il Han
authors.initials: IH
authors.lastname: Song
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002272:Carcinoembryonic Antigen / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000378:metabolism* / Q000601:surgery; D004724:Endoscopy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D010808:Physical Examination; D049268:Positron-Emission Tomography; D011184:Postoperative Period; D012008:Recurrence; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D002272:Carcinoembryonic Antigen; D019788:Fluorodeoxyglucose F18