title: Early metabolic response evaluation by fluorine-18 fluorodeoxyglucose positron emission tomography allows in vivo testing of chemosensitivity in gastric cancer: long-term results of a prospective study.
abstract: OBJECTIVE
  We prospectively evaluated the predictive value of positron emission tomography using fluorine-18 fluorodeoxyglucose (FDG-PET) for in vivo testing of chemosensitivity in locally advanced gastric cancer using an a priori definition of metabolic response (a decrease of >35% of the standard uptake value). The goal of the study was the definition of biologically different groups of patients prior to or early during induction therapy, with special emphasis on FDG non-avid tumors.
  
  
  METHODS
  Based on our data, which was published in 2003, at least 36 patients with metabolic response or FDG non-avid tumors had to be recruited for an analysis of the group of FDG non-avid tumors with sufficient statistical power. Seventy-one patients (32 metabolic nonresponders, 17 metabolic responders, and 22 patients with FDG non-avid tumors) underwent FDG-PET at baseline. In FDG-avid tumors, FDG-PET was repeated 14 days after the initiation of chemotherapy.
  
  
  RESULTS
  Metabolic responders (17 of 49) showed a high histopathologic response rate (69%) and a favorable prognosis (median survival not reached), whereas metabolic nonresponders (32 of 49) had a poor prognosis (median survival, 24.1 months) and showed a histopathologic response in 17%. The histopathologic response rate (24%) for FDG-PET non-avid patients showed no significant difference compared with FDG-avid nonresponders (P=0.72). Survival of FDG non-avid patients was 36.7 months (not significantly different from FDG-avid nonresponders, 24.1 months, P=0.46).
  
  
  CONCLUSIONS
  In locally advanced gastric cancer, three different metabolic groups exist. Response and survival was predicted by PET in FDG-avid tumors. Metabolic response assessment was not possible in FDG non-avid tumors; however, due to unfavorable outcome, therapy modification might also be considered in FDG non-avid tumors.
authors.affiliation: Department of Surgery, Technische Universität München, Munich, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Ott
authors.forename: Ken
authors.initials: K
authors.lastname: Herrmann
authors.forename: Florian
authors.initials: F
authors.lastname: Lordick
authors.forename: Hinrich
authors.initials: H
authors.lastname: Wieder
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Weber
authors.forename: Karen
authors.initials: K
authors.lastname: Becker
authors.forename: Andreas K
authors.initials: AK
authors.lastname: Buck
authors.forename: Martin
authors.initials: M
authors.lastname: Dobritz
authors.forename: Ulrich
authors.initials: U
authors.lastname: Fink
authors.forename: Kurt
authors.initials: K
authors.lastname: Ulm
authors.forename: Tibor
authors.initials: T
authors.lastname: Schuster
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.forename: Jörg-Rüdiger
authors.initials: JR
authors.lastname: Siewert
authors.forename: Bernd J
authors.initials: BJ
authors.lastname: Krause
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000378:metabolism; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000401:mortality; D013995:Time
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18