title: Preoperative N staging of gastric cancer by stomach protocol computed tomography.
abstract: OBJECTIVE
  Clinical stage of gastric cancer is currently assessed by computed tomography. Accurate clinical staging is important for the tailoring of therapy. This study evaluated the accuracy of clinical N staging using stomach protocol computed tomography.
  
  
  METHODS
  Between March 2004 and November 2012, 171 patients with gastric cancer underwent preoperative stomach protocol computed tomography (Jeju National University Hospital; Jeju, Korea). Their demographic and clinical characteristics were reviewed retrospectively. Two radiologists evaluated cN staging using axial and coronal computed tomography images, and cN stage was matched with pathologic results. The diagnostic accuracy of stomach protocol computed tomography for clinical N staging and clinical characteristics associated with diagnostic accuracy were evaluated.
  
  
  RESULTS
  The overall accuracy of stomach protocol computed tomography for cN staging was 63.2%. Computed tomography images of slice thickness 3.0 mm had a sensitivity of 60.0%; a specificity of 89.6%; an accuracy of 78.4%; and a positive predictive value of 78.0% in detecting lymph node metastases. Underestimation of cN stage was associated with larger tumor size (P<0.001), undifferentiated type (P=0.003), diffuse type (P=0.020), more advanced pathologic stage (P<0.001), and larger numbers of harvested and metastatic lymph nodes (P<0.001 each). Tumor differentiation was an independent factor affecting underestimation by computed tomography (P=0.045).
  
  
  CONCLUSIONS
  Computed tomography with a size criterion of 8 mm is highly specific but relatively insensitive in detecting nodal metastases. Physicians should keep in mind that computed tomography may not be an appropriate tool to detect nodal metastases for choosing appropriate treatment.
authors.affiliation: Department of Surgery, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Jeong Jae
authors.initials: JJ
authors.lastname: Kim
authors.forename: Jeong Sub
authors.initials: JS
authors.lastname: Lee
authors.forename: Seung Hyoung
authors.initials: SH
authors.lastname: Kim
authors.forename: Bong Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Maeng
authors.forename: Chang Lim
authors.initials: CL
authors.lastname: Hyun
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Kim
authors.forename: In Ho
authors.initials: IH
authors.lastname: Jeong
keywords: Neoplasm staging; Stomach neoplasms; Technology, radiologic