title: Zone-size nonuniformity of 18F-FDG PET regional textural features predicts survival in patients with oropharyngeal cancer.
abstract: OBJECTIVE
  The question as to whether the regional textural features extracted from PET images predict prognosis in oropharyngeal squamous cell carcinoma (OPSCC) remains open. In this study, we investigated the prognostic impact of regional heterogeneity in patients with T3/T4 OPSCC.
  
  
  METHODS
  We retrospectively reviewed the records of 88 patients with T3 or T4 OPSCC who had completed primary therapy. Progression-free survival (PFS) and disease-specific survival (DSS) were the main outcome measures. In an exploratory analysis, a standardized uptake value of 2.5 (SUV 2.5) was taken as the cut-off value for the detection of tumour boundaries. A fixed threshold at 42 % of the maximum SUV (SUVmax 42 %) and an adaptive threshold method were then used for validation. Regional textural features were extracted from pretreatment (18)F-FDG PET/CT images using the grey-level run length encoding method and grey-level size zone matrix. The prognostic significance of PET textural features was examined using receiver operating characteristic (ROC) curves and Cox regression analysis.
  
  
  RESULTS
  Zone-size nonuniformity (ZSNU) was identified as an independent predictor of PFS and DSS. Its prognostic impact was confirmed using both the SUVmax 42 % and the adaptive threshold segmentation methods. Based on (1) total lesion glycolysis, (2) uniformity (a local scale texture parameter), and (3) ZSNU, we devised a prognostic stratification system that allowed the identification of four distinct risk groups. The model combining the three prognostic parameters showed a higher predictive value than each variable alone.
  
  
  CONCLUSIONS
  ZSNU is an independent predictor of outcome in patients with advanced T-stage OPSCC, and may improve their prognostic stratification.
authors.affiliation: Departments of Nuclear Medicine, Chang Gung Memorial Hospital and Chang Gung University, Taiyuan, Taiwan.
authors.forename: Nai-Ming
authors.initials: NM
authors.lastname: Cheng
authors.forename: Yu-Hua Dean
authors.initials: YH
authors.lastname: Fang
authors.forename: Li-yu
authors.initials: LY
authors.lastname: Lee
authors.forename: Joseph Tung-Chieh
authors.initials: JT
authors.lastname: Chang
authors.forename: Din-Li
authors.initials: DL
authors.lastname: Tsan
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
authors.forename: Hung-Ming
authors.initials: HM
authors.lastname: Wang
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Liao
authors.forename: Lan-Yan
authors.initials: LY
authors.lastname: Yang
authors.forename: Ching-Han
authors.initials: CH
authors.lastname: Hsu
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009959:Oropharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18