title: Limited value of 18F-FDG PET/CT and S-100B tumour marker in the detection of liver metastases from uveal melanoma compared to liver metastases from cutaneous melanoma.
abstract: OBJECTIVE
  The objective of this study was to evaluate the value of (18)F-FDG PET/CT and S-100B tumour marker for the detection of liver metastases from uveal melanoma in comparison to liver metastases from cutaneous melanoma.
  
  
  METHODS
  A retrospective evaluation was conducted of 27 liver metastases in 13 patients with uveal melanoma (UM) (mean age: 56.8, range: 30-77) and 43 liver metastases in 14 patients (mean age: 57.9, range: 40-82) with cutaneous melanoma (CM) regarding size and FDG uptake by measuring the maximum standardized uptake value (SUV(max)). S-100B serum tumour markers were available in 20 patients. Cytology, histology, additional morphological imaging and follow-up served as reference standard. In nine patients liver metastases were further evaluated histologically regarding GLUT-1 and S-100 receptor expression and regarding epithelial or spindle cell growth pattern.
  
  
  RESULTS
  Of 27 liver metastases in 6 of 13 patients (46%) with UM, 16 (59%) were FDG negative, whereas all liver metastases from CM were positive. Liver metastases from UM showed significantly (p < 0.001) lower SUV(max) (mean: 3.5, range: 1.5-13.4) compared with liver metastases from CM (mean: 6.6, range: 2.3-15.3). In four of six (66.7%) patients with UM and liver metastases S-100B was normal and in two (33.3%) increased. All PET-negative liver metastases were detectable by morphological imaging (CT or MRI). S-100B was abnormal in 13 of 14 patients with liver metastases from CM. S-100B values were significantly higher (p = 0.007) in the CM patient group (mean S-100B: 10.9 microg/l, range: 0.1-115 microg/l) compared with the UM patients (mean: 0.2 microg/l, range: 0.0-0.5 microg/l). Histological work-up of the liver metastases showed no obvious difference in GLUT-1 or S-100 expression between UM and CM liver metastases. The minority (36%) of patients with UM had extrahepatic metastases and the majority (86%) of patients with CM had extrahepatic metastases, respectively. There was a close to significant trend to better survival of UM patients compared with CM patients (p = 0.06).
  
  
  CONCLUSIONS
  FDG PET/CT and serum S-100B are not sensitive enough for the detection of liver metastases from UM, whereas liver metastases from cutaneous melanoma are reliably FDG positive and lead regularly to increased S-100B tumour markers. The reason for the lower FDG uptake in UM liver metastases remains unclear. We recommend to perform combined contrast-enhanced PET/CT in order to detect FDG-negative liver metastases from UM.
authors.affiliation: Division of Nuclear Medicine, Department of Medical Radiology, University Hospital Zurich, 8091 Zurich, Switzerland. klaus.strobel@usz.ch
authors.forename: K
authors.initials: K
authors.lastname: Strobel
authors.forename: B
authors.initials: B
authors.lastname: Bode
authors.forename: R
authors.initials: R
authors.lastname: Dummer
authors.forename: P
authors.initials: P
authors.lastname: Veit-Haibach
authors.forename: D R
authors.initials: DR
authors.lastname: Fischer
authors.forename: L
authors.initials: L
authors.lastname: Imhof
authors.forename: S
authors.initials: S
authors.lastname: Goldinger
authors.forename: Hans C
authors.initials: HC
authors.lastname: Steinert
authors.forename: G K
authors.initials: GK
authors.lastname: von Schulthess
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism / Q000556:secondary*; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D009414:Nerve Growth Factors / Q000097:blood*; D049268:Positron-Emission Tomography; D011379:Prognosis; D012189:Retrospective Studies; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood*; D012878:Skin Neoplasms / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D014604:Uveal Neoplasms / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D019788:Fluorodeoxyglucose F18