title: Assessment of lymph node metastases using 18F-FDG PET in patients with advanced gastric cancer.
abstract: OBJECTIVE
  The aim of this study was to assess the diagnostic accuracy of (18)F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) with respect to lymph node (LN) metastasis in patients with advanced gastric cancer, and to ascertain the factors that affect this accuracy.
  
  
  METHODS
  Seventy-three patients with advanced gastric cancer, verified in all cases by endoscopic biopsy, were enrolled in this prospective study. We conducted FDG PET and other routine preoperative studies, including abdominal computed tomography (CT). Patients underwent either curative-intent gastrectomy and lymphadenectomy (n = 67) or exploratory laparotomy. The Japanese system for the classification of gastric cancer was used for LN assessment.
  
  
  RESULTS
  FDG PET was able to detect primary lesions in 70 of the 73 cases. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value of FDG PET for LN metastasis were 40%, 95%, 91% and 56%, respectively. Signet-ring cell carcinoma was associated with the lowest sensitivity (15%), whereas other cell types could be detected with moderate sensitivity (30-71%) and high specificity (93-100%). According to multiple logistic regression, the standardised uptake value for primary tumours was the only independent variable to be significantly related to sensitivity for LN metastasis (p = 0.02, odds ratio = 1.14). CT was superior to PET in terms of sensitivity (p < 0.0001), and PET was superior to CT in terms of specificity (p < 0.0001) and PPV (p = 0.05).
  
  
  CONCLUSIONS
  FDG PET exhibits good specificity for LN staging of gastric cancer, and FDG uptake in the primary tumour is significantly related to the accuracy of FDG PET. Despite some clear limitations, FDG PET proved useful in the LN staging of FDG-avid gastric cancer.
authors.affiliation: Research Institute and Hospital, National Cancer Center, 809 Madu Ilsan Goyang, Gyeonggi, South Korea.
authors.forename: Seok-Ki
authors.initials: SK
authors.lastname: Kim
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
authors.forename: Jong Seok
authors.initials: JS
authors.lastname: Lee
authors.forename: Hark Kyun
authors.initials: HK
authors.lastname: Kim
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Chang
authors.forename: Jin Yi
authors.initials: JY
authors.lastname: Choi
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Keun Won
authors.initials: KW
authors.lastname: Ryu
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Kim
authors.forename: Jae-Moon
authors.initials: JM
authors.lastname: Bae
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18