title: Pretreatment 18F-FDG PET Textural Features in Locally Advanced Non-Small Cell Lung Cancer: Secondary Analysis of ACRIN 6668/RTOG 0235.
abstract: In a secondary analysis of American College of Radiology Imaging Network (ACRIN) 6668/RTOG 0235, high pretreatment metabolic tumor volume (MTV) on (18)F-FDG PET was found to be a poor prognostic factor for patients treated with chemoradiotherapy for locally advanced non-small cell lung cancer (NSCLC). Here we utilize the same dataset to explore whether heterogeneity metrics based on PET textural features can provide additional prognostic information.
  
  
  
  Patients with locally advanced NSCLC underwent (18)F-FDG PET prior to treatment. A gradient-based segmentation tool was used to contour each patient's primary tumor. MTV, maximum SUV, and 43 textural features were extracted for each tumor. To address overfitting and high collinearity among PET features, the least absolute shrinkage and selection operator (LASSO) method was applied to identify features that were independent predictors of overall survival (OS) after adjusting for MTV. Recursive binary partitioning in a conditional inference framework was utilized to identify optimal thresholds. Kaplan-Meier curves and log-rank testing were used to compare outcomes among patient groups.
  
  
  
  Two hundred one patients met inclusion criteria. The LASSO procedure identified 1 textural feature (SumMean) as an independent predictor of OS. The optimal cutpoint for MTV was 93.3 cm(3), and the optimal SumMean cutpoint for tumors above 93.3 cm(3) was 0.018. This grouped patients into three categories: low tumor MTV (n = 155; median OS, 22.6 mo), high tumor MTV and high SumMean (n = 23; median OS, 20.0 mo), and high tumor MTV and low SumMean (n = 23; median OS, 6.2 mo; log-rank P < 0.001).
  
  
  
  We have described an appropriate methodology to evaluate the prognostic value of textural PET features in the context of established prognostic factors. We have also identified a promising feature that may have prognostic value in locally advanced NSCLC patients with large tumors who are treated with chemoradiotherapy. Validation studies are warranted.
authors.affiliation: Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York ohri.nitin@gmail.com.
authors.forename: Nitin
authors.initials: N
authors.lastname: Ohri
authors.affiliation: Department of Biostatistics and Center for Statistical Sciences, Brown University School of Public Health, Providence, Rhode Island.
authors.forename: Fenghai
authors.initials: F
authors.lastname: Duan
authors.affiliation: Department of Biostatistics and Center for Statistical Sciences, Brown University School of Public Health, Providence, Rhode Island.
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Snyder
authors.affiliation: Emory University, Atlanta, Georgia.
authors.forename: Bo
authors.initials: B
authors.lastname: Wei
authors.affiliation: Department of Radiation Oncology, University Hospitals Seidman Cancer Center, Case Comprehensive Cancer Center and Case Western Reserve University, Cleveland, Ohio.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Machtay
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Abass
authors.initials: A
authors.lastname: Alavi
authors.affiliation: Mallinckrodt Institute of Radiology and the Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Barry A
authors.initials: BA
authors.lastname: Siegel
authors.affiliation: Department of Radiation Oncology, Baptist Cancer Institute, Jacksonville, Florida.
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Johnson
authors.affiliation: Mallinckrodt Institute of Radiology and the Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Bradley
authors.affiliation: Department of Radiation Oncology, Lankenau Hospital and Lankenau Institute for Medical Research, Lower Merion, Pennsylvania.
authors.forename: Albert
authors.initials: A
authors.lastname: DeNittis
authors.affiliation: Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania; and.
authors.forename: Maria
authors.initials: M
authors.lastname: Werner-Wasik
authors.affiliation: University of Michigan Ann Arbor, Ann Arbor, Michigan.
authors.forename: Issam
authors.initials: I
authors.lastname: El Naqa
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011379:Prognosis; D016016:Proportional Hazards Models; D047368:Tumor Burden
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: 18FDG-PET; chemoradiotherapy; non–small cell lung cancer; textural features