title: Spatial-temporal [¹⁸F]FDG-PET features for predicting pathologic response of esophageal cancer to neoadjuvant chemoradiation therapy.
abstract: OBJECTIVE
  To extract and study comprehensive spatial-temporal (18)F-labeled fluorodeoxyglucose ([(18)F]FDG) positron emission tomography (PET) features for the prediction of pathologic tumor response to neoadjuvant chemoradiation therapy (CRT) in esophageal cancer.
  
  
  METHODS
  Twenty patients with esophageal cancer were treated with trimodal therapy (CRT plus surgery) and underwent [(18)F]FDG-PET/CT scans both before (pre-CRT) and after (post-CRT) CRT. The 2 scans were rigidly registered. A tumor volume was semiautomatically delineated using a threshold standardized uptake value (SUV) of ≥2.5, followed by manual editing. Comprehensive features were extracted to characterize SUV intensity distribution, spatial patterns (texture), tumor geometry, and associated changes resulting from CRT. The usefulness of each feature in predicting pathologic tumor response to CRT was evaluated using the area under the receiver operating characteristic curve (AUC) value.
  
  
  RESULTS
  The best traditional response measure was decline in maximum SUV (SUVmax; AUC, 0.76). Two new intensity features, decline in mean SUV (SUVmean) and skewness, and 3 texture features (inertia, correlation, and cluster prominence) were found to be significant predictors with AUC values ≥0.76. According to these features, a tumor was more likely to be a responder when the SUVmean decline was larger, when there were relatively fewer voxels with higher SUV values pre-CRT, or when [(18)F]FDG uptake post-CRT was relatively homogeneous. All of the most accurate predictive features were extracted from the entire tumor rather than from the most active part of the tumor. For SUV intensity features and tumor size features, changes were more predictive than pre- or post-CRT assessment alone.
  
  
  CONCLUSIONS
  Spatial-temporal [(18)F]FDG-PET features were found to be useful predictors of pathologic tumor response to neoadjuvant CRT in esophageal cancer.
authors.affiliation: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
authors.forename: Shan
authors.initials: S
authors.lastname: Tan
authors.forename: Seth
authors.initials: S
authors.lastname: Kligerman
authors.forename: Wengen
authors.initials: W
authors.lastname: Chen
authors.forename: Minh
authors.initials: M
authors.lastname: Lu
authors.forename: Grace
authors.initials: G
authors.lastname: Kim
authors.forename: Steven
authors.initials: S
authors.lastname: Feigenberg
authors.forename: Warren D
authors.initials: WD
authors.lastname: D'Souza
authors.forename: Mohan
authors.initials: M
authors.lastname: Suntharalingam
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D019540:Area Under Curve; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D059186:Chemoradiotherapy, Adjuvant / Q000379:methods*; D002945:Cisplatin / Q000008:administration & dosage; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D020360:Neoadjuvant Therapy / Q000379:methods*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies; D062211:Spatio-Temporal Analysis; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002945:Cisplatin; D005472:Fluorouracil