title: Fluorodeoxyglucose positron emission tomography fails to detect distant metastases at initial staging of melanoma patients with metastatic involvement of sentinel lymph node.
abstract: BACKGROUND
  Positron emission tomography (PET) using fluorodeoxyglucose (FDG) has proven to be more sensitive and accurate than other imaging modalities for the detection of distant metastases in patients with melanoma. Sentinel lymph node (SLN) status is the most important prognostic factor in melanoma patients with no evidence of distant metastasis.
  
  
  OBJECTIVE
  To assess the rate of distant metastases in patients with a positive SLN biopsy (SLNB).
  
  
  METHODS
  Forty-six consecutive patients with a positive SLNB underwent PET or PET-computed tomography within 6 weeks of the SLNB procedure. The patients did not present any clinical sign of nodal involvement or of distant metastasis. PET findings were classified as positive, negative or nonconclusive.
  
  
  RESULTS
  No patient had a positive PET scan for distant metastasis. Six patients (13%) had a nonconclusive PET scan; none of them presented distant metastasis within 12 months. Forty patients (87%) had a negative PET scan; among them five (12%) presented with distant metastasis within 12 months.
  
  
  CONCLUSIONS
  Fluorodeoxyglucose positron emission tomography failed to detect distant metastases at initial staging in patients with a positive SLNB, even in patients who presented with distant metastases within 12 months after the FDG PET scan. These results could be explained by the low prevalence of macroscopic metastatic disease at this stage and by the important delay between the onset of the spread of microscopic metastatic disease and the identification by PET scan of macroscopic metastatic disease.
authors.affiliation: Nuclear Medicine Department, Toulouse Purpan University Hospital, Place du Dr Baylac, TSA 40031, Toulouse cedex 31059, France. thomwagner@hotmail.com
authors.forename: T
authors.initials: T
authors.lastname: Wagner
authors.forename: N
authors.initials: N
authors.lastname: Meyer
authors.forename: S
authors.initials: S
authors.lastname: Zerdoud
authors.forename: A
authors.initials: A
authors.lastname: Julian
authors.forename: C
authors.initials: C
authors.lastname: Chevreau
authors.forename: P
authors.initials: P
authors.lastname: Payoux
authors.forename: F
authors.initials: F
authors.lastname: Courbon
mesh_terms: D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging / Q000379:methods; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18