title: FDG PET in patients with cancer of an unknown primary.
abstract: BACKGROUND
  This prospective study was undertaken to address the capacity of positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) to determine the primary tumour site of carcinomas with unknown primary site.
  
  
  METHODS
  Twenty-five patients with metastases from adenocarcinoma or undifferentiated carcinoma of unknown primary site (CUP) were included prospectively. For all patients, extensive imaging was unsuccessful in localizing the primary site. Patients received 370 MBq of 18F-FDG intravenously, and whole-body images were acquired 60 min after injection. All hot spots that could not be attributed to a metastatic site were considered as the primary tumour. The evaluation of FDG PET data was based on clinical and radiological outcome or surgery if indicated.
  
  
  RESULTS
  Twenty-four patients were eligible for analysis. All known metastases were visualized. In six patients, FDG PET showed a primary tumour site which was confirmed by follow-up or surgery. In five patients, the primary tumour site was suggested by FDG PET but not confirmed by clinical outcome. No primary tumour was found in the other patients, with a mean follow-up of 15 months.
  
  
  CONCLUSIONS
  In our series, FDG PET allowed the identification of primary tumour site in one quarter of patients with CUP (6/24). We conclude that FDG PET has a place in the initial staging of these patients.
authors.affiliation: European Association for Research in Oncology, Department of Medical Oncology, Henri Mondor Hospital, Assistance Publique - Hopitaux de Paris, Lille, France. h-gauthier@o-lambret.fr
authors.forename: Hélène
authors.initials: H
authors.lastname: Kolesnikov-Gauthier
authors.forename: Eric
authors.initials: E
authors.lastname: Levy
authors.forename: Pascal
authors.initials: P
authors.lastname: Merlet
authors.forename: Julia
authors.initials: J
authors.lastname: Kirova
authors.forename: Andre
authors.initials: A
authors.lastname: Syrota
authors.forename: Philippe
authors.initials: P
authors.lastname: Carpentier
authors.forename: Michel
authors.initials: M
authors.lastname: Meignan
authors.forename: Pascal
authors.initials: P
authors.lastname: Piedbois
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology; D000328:Adult; D000368:Aged; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis* / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014915:Whole-Body Counting
chemical_list: D019788:Fluorodeoxyglucose F18