title: 18F-FLT and 18F-FDG positron emission tomography for the imaging of advanced well-differentiated gastro-entero-pancreatic endocrine tumours.
abstract: OBJECTIVE
  Gastro-entero-pancreatic (GEP) endocrine tumours are a heterogenous group of tumours of variable localization and prognosis. It has been suggested that positron emission tomography (PET) using 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) may have a prognostic value and help to identify patients at risk of progression. [18F]fluoro-3'-deoxy-3'-L-fluorothymidine (18F-FLT) has been recently developed as a PET proliferation tracer. At present, there are no studies investigating its role in GEP. The aim of this prospective study was to assess the value of 18F-FLT-PET for the evaluation of GEP.
  
  
  METHODS
  Ten patients with biopsy-proven locally advanced or metastasized, well-differentiated GEP neuroendocrine tumours were prospectively enrolled and scheduled for 18F-FDG and 18F-FLT-PET. Images were compared with other conventional diagnostic procedures, namely computed tomography, ultrasound, somatostatin receptor scintigraphy and with clinical and diagnostic follow-up.
  
  
  RESULTS
  Evaluation criteria were interpreted in terms of assumed presence of tumoral tissue. According to the patient's status, FDG was positive in five out of the seven patients with stable disease and in two out of the three patients with progressive disease. No positive case was identified by 18F-FLT in either the primary or the metastatic tumour site, whatever the status of patients, and this was probably a reflection of the slow proliferation rate of tumours.
  
  
  CONCLUSIONS
  These preliminary data suggest that 18F-FLT-PET is not a suitable tracer for the evaluation of advanced well-differentiated GEP tumours. FDG showed good diagnostic performance but does not help to identify patients at risk of progression.
authors.affiliation: Nuclear Medicine Department, Hospices Civils de Lyon, Lyon-Sud Hospital, France. francesco.giammarile@chu-lyon.fr
authors.forename: Francesco
authors.initials: F
authors.lastname: Giammarile
authors.forename: Claire
authors.initials: C
authors.lastname: Billotey
authors.forename: Catherine
authors.initials: C
authors.lastname: Lombard-Bohas
authors.forename: Didier
authors.initials: D
authors.lastname: Le Bars
authors.forename: Claire
authors.initials: C
authors.lastname: Bournaud
authors.forename: Sandrine
authors.initials: S
authors.lastname: Masson
authors.forename: Thomas
authors.initials: T
authors.lastname: Walter
authors.forename: Claire
authors.initials: C
authors.lastname: Houzard
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Scoazec
authors.forename: Valérie
authors.initials: V
authors.lastname: Hervieu
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Vuillez
authors.forename: Catherine
authors.initials: C
authors.lastname: Cornu
authors.forename: Marc
authors.initials: M
authors.lastname: Janier
authors.forename: Françoise
authors.initials: F
authors.lastname: Borson-Chazot
mesh_terms: D000328:Adult; D000368:Aged; D002454:Cell Differentiation; D015224:Dideoxynucleosides; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007414:Intestinal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology
chemical_list: D015224:Dideoxynucleosides; D019788:Fluorodeoxyglucose F18; C002854:alovudine