title: Quantitative assessment of the asphericity of pretherapeutic FDG uptake as an independent predictor of outcome in NSCLC.
abstract: BACKGROUND
  The aim of the present study was to evaluate the predictive value of a novel quantitative measure for the spatial heterogeneity of FDG uptake, the asphericity (ASP) in patients with non-small cell lung cancer (NSCLC).
  
  
  METHODS
  FDG-PET/CT had been performed in 60 patients (15 women, 45 men; median age, 65.5 years) with newly diagnosed NSCLC prior to therapy. The FDG-PET image of the primary tumor was segmented using the ROVER 3D segmentation tool based on thresholding at the volume-reproducing intensity threshold after subtraction of local background. ASP was defined as the relative deviation of the tumor's shape from a sphere. Univariate and multivariate Cox regression as well as Kaplan-Meier (KM) analysis and log-rank test with respect to overall (OAS) and progression-free survival (PFS) were performed for clinical variables, SUVmax/mean, metabolically active tumor volume (MTV), total lesion glycolysis (TLG), ASP and "solidity", another measure of shape irregularity.
  
  
  RESULTS
  ASP, solidity and "primary surgical treatment" were significant independent predictors of PFS in multivariate Cox regression with binarized parameters (HR, 3.66; p<0.001, HR, 2.11; p=0.05 and HR, 2.09; p=0.05), ASP and "primary surgical treatment" of OAS (HR, 3.19; p=0.02 and HR, 3.78; p=0.01, respectively). None of the other semi-quantitative PET parameters showed significant predictive value with respect to OAS or PFS. Kaplan-Meier analysis revealed a probability of 2-year PFS of 52% in patients with low ASP compared to 12% in patients with high ASP (p<0.001). Furthermore, it showed a higher OAS rate in the case of low versus high ASP (1-year-OAS, 91% vs. 67%: p=0.02).
  
  
  CONCLUSIONS
  The novel parameter asphericity of pretherapeutic FDG uptake seems to provide better prognostic value for PFS and OAS in NCSLC compared to SUV, metabolic tumor volume, total lesion glycolysis and solidity.
authors.affiliation: Clinic of Radiology and Nuclear Medicine, University Hospital, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, Magdeburg, Germany. Ivayla.apostolova@med.ovgu.de.
authors.forename: Ivayla
authors.initials: I
authors.lastname: Apostolova
authors.forename: Julian
authors.initials: J
authors.lastname: Rogasch
authors.forename: Ralph
authors.initials: R
authors.lastname: Buchert
authors.forename: Heinz
authors.initials: H
authors.lastname: Wertzel
authors.forename: H Jost
authors.initials: HJ
authors.lastname: Achenbach
authors.forename: Jens
authors.initials: J
authors.lastname: Schreiber
authors.forename: Sandra
authors.initials: S
authors.lastname: Riedel
authors.forename: Christian
authors.initials: C
authors.lastname: Furth
authors.forename: Alexandr
authors.initials: A
authors.lastname: Lougovski
authors.forename: Georg
authors.initials: G
authors.lastname: Schramm
authors.forename: Frank
authors.initials: F
authors.lastname: Hofheinz
authors.forename: Holger
authors.initials: H
authors.lastname: Amthauer
authors.forename: Ingo G
authors.initials: IG
authors.lastname: Steffen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18