title: Textural features in pre-treatment [F18]-FDG-PET/CT are correlated with risk of local recurrence and disease-specific survival in early stage NSCLC patients receiving primary stereotactic radiation therapy.
abstract: BACKGROUND
  Textural features in FDG-PET have been shown to provide prognostic information in a variety of tumor entities. Here we evaluate their predictive value for recurrence and prognosis in NSCLC patients receiving primary stereotactic radiation therapy (SBRT).
  
  
  METHODS
  45 patients with early stage NSCLC (T1 or T2 tumor, no lymph node or distant metastases) were included in this retrospective study and followed over a median of 21.4 months (range 3.1-71.1). All patients were considered non-operable due to concomitant disease and referred to SBRT as the primary treatment modality. Pre-treatment FDG-PET/CT scans were obtained from all patients. SUV and volume-based analysis as well as extraction of textural features based on neighborhood gray-tone difference matrices (NGTDM) and gray-level co-occurence matrices (GLCM) were performed using InterView Fusion™ (Mediso Inc., Budapest). The ability to predict local recurrence (LR), lymph node (LN) and distant metastases (DM) was measured using the receiver operating characteristic (ROC). Univariate and multivariate analysis of overall and disease-specific survival were executed.
  
  
  RESULTS
  7 out of 45 patients (16%) experienced LR, 11 (24%) LN and 11 (24%) DM. ROC revealed a significant correlation of several textural parameters with LR with an AUC value for entropy of 0.872. While there was also a significant correlation of LR with tumor size in the overall cohort, only texture was predictive when examining T1 (tumor diameter < = 3 cm) and T2 (>3 cm) subgroups. No correlation of the examined PET parameters with LN or DM was shown. In univariate survival analysis, both heterogeneity and tumor size were predictive for disease-specific survival, but only texture determined by entropy was determined as an independent factor in multivariate analysis (hazard ratio 7.48, p = .016). Overall survival was not significantly correlated to any examined parameter, most likely due to the high comorbidity in our cohort.
  
  
  CONCLUSIONS
  Our study adds to the growing evidence that tumor heterogeneity as described by FDG-PET texture is associated with response to radiation therapy in NSCLC. The results may be helpful into identifying patients who might profit from an intensified treatment regime, but need to be verified in a prospective patient cohort before being incorporated into routine clinical practice.
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der TU München, Ismaninger Str, Munich, Germany. thomas.pyka@tum.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pyka
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der TU München, Ismaninger Str, Munich, Germany. ralph.bundschuh@ukb.uni-bonn.de.|Klinik und Poliklinik für Nuklearmedizin, Rheinische Friedrich-Wilhelms-Universität Bonn, Sigmund-Freud-Straße, Bonn, Germany. ralph.bundschuh@ukb.uni-bonn.de.
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Bundschuh
authors.affiliation: Klinik für Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar der TU München, Ismaninger Str, Munich, Germany. Nicolaus.Andratschke@usz.ch.|Klinik für Radio-Onkologie, UniversitätsSpital Zürich, Rämistrasse, Zurich, Switzerland. Nicolaus.Andratschke@usz.ch.
authors.forename: Nicolaus
authors.initials: N
authors.lastname: Andratschke
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der TU München, Ismaninger Str, Munich, Germany. wellenspiel@gmx.net.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Mayer
authors.affiliation: Klinik für Strahlentherapie und Radiologische Onkologie, Klinikum rechts der Isar der TU München, Ismaninger Str, Munich, Germany. Hanno.Specht@mri.tum.de.
authors.forename: Hanno M
authors.initials: HM
authors.lastname: Specht
authors.affiliation: Mediso Medical Imaging Systems, Alsotorokvesz, Budapest, Hungary. laszlo.papp@mediso.com.
authors.forename: Laszló
authors.initials: L
authors.lastname: Papp
authors.affiliation: Mediso Medical Imaging Systems, Alsotorokvesz, Budapest, Hungary. norbert.zsoter@mediso.hu.
authors.forename: Norbert
authors.initials: N
authors.lastname: Zsótér
authors.affiliation: Klinik und Poliklinik für Nuklearmedizin, Rheinische Friedrich-Wilhelms-Universität Bonn, Sigmund-Freud-Straße, Bonn, Germany. markus.essler@ukb.uni-bonn.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Essler
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18