title: Extranodal metastasis is an indicator of poor prognosis in patients with gastric carcinoma.
abstract: BACKGROUND
  The aim of this study was to determine the clinical significance and prognostic impact of extranodal metastasis (EM) in gastric carcinoma.
  
  
  METHODS
  The study included 1023 patients who underwent gastrectomy with lymphadenectomy for primary gastric carcinoma between January 1993 and December 1996. EM was defined as the presence of tumour cells in extramural soft tissue that was discontinuous with either the primary lesion or locoregional lymph nodes.
  
  
  RESULTS
  EM was detected in 146 (14.3 per cent) of the 1023 patients and in 1060 (3.0 per cent) of the 35 811 nodules that were retrieved as 'lymph nodes' from adipose connective tissues. The incidence of EM was significantly higher in patients with tumours that were large (diameter 10 cm or more), infiltrative, deeply invading or undifferentiated and in those with lymph node, peritoneal or liver metastases, or lymphatic or vascular involvement. After curative operation overall survival was significantly worse for patients with EM than those without (P < 0.001). Multivariate analysis identified EM as an independent prognostic factor (hazard ratio 1.82 (95 per cent confidence interval 1.23 to 2.71); P = 0.003).
  
  
  CONCLUSIONS
  EM is an independent prognostic factor and should therefore be included in the tumour node metastasis (TNM) staging system.
authors.affiliation: Gastric Surgery Division, National Cancer Centre Hospital, 5-1-1 Tsukiji-Chuoku, 104-0045, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Etoh
authors.forename: M
authors.initials: M
authors.lastname: Sasako
authors.forename: K
authors.initials: K
authors.lastname: Ishikawa
authors.forename: H
authors.initials: H
authors.lastname: Katai
authors.forename: T
authors.initials: T
authors.lastname: Sano
authors.forename: T
authors.initials: T
authors.lastname: Shimoda
mesh_terms: D000368:Aged; D005260:Female; D005743:Gastrectomy / Q000379:methods; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010534:Peritoneal Neoplasms / Q000556:secondary*; D011379:Prognosis; D018709:Statistics, Nonparametric; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery; D016019:Survival Analysis