title: Textural Parameters of Tumor Heterogeneity in ¹⁸F-FDG PET/CT for Therapy Response Assessment and Prognosis in Patients with Locally Advanced Rectal Cancer.
abstract: (18)F-FDG PET/CT is effective in the assessment of therapy response. Changes in glucose uptake or tumor size are used as a measure. Tumor heterogeneity was found to be a promising predictive and prognostic factor. We investigated textural parameters for their predictive and prognostic capability in patients with rectal cancer using histopathology as the gold standard. In addition, a comparison to clinical outcome was performed.
  
  
  METHODS
  Twenty-seven patients with rectal cancer underwent (18)F-FDG PET/CT before, 2 wk after the start, and 4 wk after the completion of neoadjuvant chemoradiotherapy. In all PET/CT scans, conventional parameters (tumor volume, diameter, maximum and mean standardized uptake values, and total lesion glycolysis [TLG]) and textural parameters (coefficient of variation [COV], skewness, and kurtosis) were determined to assess tumor heterogeneity. Values on pretherapeutic PET/CT as well as changes early in the course of therapy and after therapy were compared with histopathologic response. In addition, the prognostic value was assessed by correlation with time to progression and survival time.
  
  
  RESULTS
  The COV showed a statistically significant capability to assess histopathologic response early in therapy (sensitivity, 68%; specificity, 88%) and after therapy (79% and 88%, respectively). Thereby, the COV had a higher area under the curve in receiver-operating-characteristic analysis than did any analyzed conventional parameter for early and late response assessment. The COV showed a statistically significant capability to evaluate disease progression and to predict survival, although the latter was not statistically significant.
  
  
  CONCLUSIONS
  Tumor heterogeneity assessed by the COV, being superior to the investigated conventional parameters, is an important predictive factor in patients with rectal cancer. Furthermore, it can provide prognostic information. Therefore, its application is an important step for personalized treatment of rectal cancer.
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Würzburg, Wuerzburg, Germany Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Bonn, Bonn, Germany bundschuh_r@klinik.uni-wuerzburg.de.
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Bundschuh
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Dinges
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
authors.forename: Larissa
authors.initials: L
authors.lastname: Neumann
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Seyfried
authors.affiliation: Mediso Medical Imaging Systems Ltd., Budapest, Hungary.
authors.forename: Norbert
authors.initials: N
authors.lastname: Zsótér
authors.affiliation: Mediso Medical Imaging Systems Ltd., Budapest, Hungary.
authors.forename: Laszló
authors.initials: L
authors.lastname: Papp
authors.affiliation: Chirurgische Klinik, Kantonsspital Baden, Baden, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Rosenberg
authors.affiliation: Institut für Pathologie, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
authors.forename: Karen
authors.initials: K
authors.lastname: Becker
authors.affiliation: Klinik und Poliklinik für Radioonkolgie und Strahlentherapie, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany; and.
authors.forename: Sabrina T
authors.initials: ST
authors.lastname: Astner
authors.affiliation: Institut für Röntgendiagnostik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Henninger
authors.affiliation: Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Würzburg, Wuerzburg, Germany.
authors.forename: Ken
authors.initials: K
authors.lastname: Herrmann
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
authors.forename: Sibylle I
authors.initials: SI
authors.lastname: Ziegler
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Bonn, Bonn, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Essler
mesh_terms: D059186:Chemoradiotherapy, Adjuvant; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D064847:Multimodal Imaging; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D011379:Prognosis; D012372:ROC Curve; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: coefficient of variation; prognostic parameter; rectal cancer; therapy monitoring; tumor heterogeneity