title: Evaluation of several FDG PET parameters for prediction of soft tissue tumour grade at primary diagnosis and recurrence.
abstract: OBJECTIVE
  This study evaluates the diagnostic accuracy of SUV-based parameters derived from [(18) F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in order to optimize non-invasive prediction of soft tissue tumour (STT) grade.
  
  
  METHODS
  One hundred and twenty-nine lesions from 123 patients who underwent FDG-PET for primary staging (n = 79) or assessment of recurrence (n = 44) of STT were analyzed retrospectively. Histopathology was the reference standard for tumour grading. Absolute values and tumour-to-liver ratios of several standardized uptake value (SUV) parameters were correlated with tumour grading.
  
  
  RESULTS
  At primary diagnosis SUVmax, SUVpeak, SUVmax/SUVliver and SUVpeak/SUVliver showed good correlation with tumour grade. SUVpeak (area under the receiver-operating-characteristic, AUC-ROC: 0.82) and SUVpeak/SUVliver (AUC-ROC: 0.82) separated best between low grade (WHO intermediate, grade 1 sarcoma, and low risk gastrointestinal stromal tumours, GISTs) and high grade (grade 2/3 sarcoma and intermediate/high risk GISTs) lesions: optimal threshold for SUVpeak/SUVliver was 2.4, which resulted in a sensitivity of 79 % and a specificity of 81 %. At disease recurrence, the AUC-ROC was <0.75 for each parameter.
  
  
  CONCLUSIONS
  A tumour SUVpeak of at least 2.4 fold mean liver uptake predicts high grade histopathology with good diagnostic accuracy at primary staging. At disease recurrence, FDG-PET does not reliably separate high and low grade lesions.
  
  
  CONCLUSIONS
  • Several SUV parameters accurately predict soft tissue sarcoma grade at primary diagnosis. • Tumour-to-liver ratios are of comparable value to absolute SUV parameters. • SUV peak /SUV liver >2.4 had 79 % sensitivity and 81 % specificity for high grade lesions. • At recurrence, FDG PET does not reliably indicate high grade sarcomas.
authors.affiliation: Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany, wolfgang.fendler@med.uni-muenchen.de.
authors.forename: Wolfgang P
authors.initials: WP
authors.lastname: Fendler
authors.forename: Rebecca P
authors.initials: RP
authors.lastname: Chalkidis
authors.forename: Harun
authors.initials: H
authors.lastname: Ilhan
authors.forename: Thomas
authors.initials: T
authors.lastname: Knösel
authors.forename: Ken
authors.initials: K
authors.lastname: Herrmann
authors.forename: Rolf D
authors.initials: RD
authors.lastname: Issels
authors.forename: Peter
authors.initials: P
authors.lastname: Bartenstein
authors.forename: Clemens C
authors.initials: CC
authors.lastname: Cyran
authors.forename: Lars H
authors.initials: LH
authors.lastname: Lindner
authors.forename: Marcus
authors.initials: M
authors.lastname: Hacker
mesh_terms: D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000473:pathology*; D049268:Positron-Emission Tomography / Q000379:methods; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012509:Sarcoma / Q000000981:diagnostic imaging / Q000473:pathology*; D012680:Sensitivity and Specificity; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18