title: Asphericity of pretherapeutic tumour FDG uptake provides independent prognostic value in head-and-neck cancer.
abstract: OBJECTIVE
  To propose a novel measure, namely the 'asphericity' (ASP), of spatial irregularity of FDG uptake in the primary tumour as a prognostic marker in head-and-neck cancer.
  
  
  METHODS
  PET/CT was performed in 52 patients (first presentation, n = 36; recurrence, n = 16). The primary tumour was segmented based on thresholding at the volume-reproducible intensity threshold after subtraction of the local background. ASP was used to characterise the deviation of the tumour's shape from sphere symmetry. Tumour stage, tumour localisation, lymph node metastases, distant metastases, SUVmax, SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were also considered. The association of overall (OAS) and progression-free survival (PFS) with these parameters was analysed.
  
  
  RESULTS
  Cox regression revealed high SUVmax [hazard ratio (HR) = 4.4/7.4], MTV (HR = 4.6/5.7), TLG (HR = 4.8/8.9) and ASP (HR = 7.8/7.4) as significant predictors with respect to PFS/OAS in case of first tumour manifestation. The combination of high MTV and ASP showed very high HRs of 22.7 for PFS and 13.2 for OAS. In case of recurrence, MTV (HR = 3.7) and the combination of MTV/ASP (HR = 4.2) were significant predictors of PFS.
  
  
  CONCLUSIONS
  ASP of pretherapeutic FDG uptake in the primary tumour improves the prediction of tumour progression in head-and-neck cancer at first tumour presentation.
  
  
  CONCLUSIONS
  Asphericity (ASP) characterises the spatial heterogeneity of FDG uptake in tumours. ASP is a promising prognostic parameter in head-and-neck cancer. ASP is useful for identification of high-risk patients with head-and-neck cancer.
authors: Department of Nuclear Medicine, Charité University Medical Center, Berlin, Germany, ivayla.apostolova@med.ovgu.de.
authors: Ivayla
authors: I
authors: Apostolova
authors: Ingo G
authors: IG
authors: Steffen
authors: Florian
authors: F
authors: Wedel
authors: Alexandr
authors: A
authors: Lougovski
authors: Simone
authors: S
authors: Marnitz
authors: Thorsten
authors: T
authors: Derlin
authors: Holger
authors: H
authors: Amthauer
authors: Ralph
authors: R
authors: Buchert
authors: Frank
authors: F
authors: Hofheinz
authors: Winfried
authors: W
authors: Brenner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D014057:Tomography, X-Ray Computed / Q000379:methods*; D047368:Tumor Burden