title: Metastatic lymph node ratio is an independent prognostic factor in gastric cancer.
abstract: OBJECTIVE
  The metastatic status of the regional lymph node is the most significant prognostic factor for gastric cancer. However, diverse prognoses are evident even among the same N classifications of the current tumor-node-metastasis system. The aim of this study is to evaluate the prognostic significance of the ratio of metastatic to examined lymph nodes (N ratio) for identifying a high-risk subgroup of patients with gastric cancer.
  
  
  METHODS
  The postoperative survival of 264 consecutive patients with operable gastric cancer was analyzed with regard to its N ratio and current N classification. Survival was determined by the Kaplan-Meier method and differences were assessed by the log-rank test. Multivariate analysis was performed using the Cox proportional hazards model in forward stepwise regression.
  
  
  RESULTS
  The lymph node ratio was classified as follows N ratio 1, 1 to 10, N ratio 2, 11 to 25; and N ratio 3, >25. The 5-year survival rates stratified by N ratio were N ratio 1, 81%; N ratio 2, 49%; N ratio 3, 25%. The rates of survival were significantly different according to the N ratio in pN1 and pN2 classification of the UICC/TNM classification (p<0.05). Cox regression analysis revealed that N ratio was sensitive prognostic factor in these surgically treated patients, which were also significantly correlated with extent of lymph node dissection and pathologic tumor stage (p<0.05).
  
  
  CONCLUSIONS
  N ratio can be recommended as an applicable parameter for lymph node involvement of gastric cancer. It is a more effective and precise indicator for prognostic stratification of patients with lymph node positive gastric cancer than the current N classification of the tumor-node-metastasis system.
authors.affiliation: Department of Surgery, Istanbul Medical School, Istanbul University, Capa, Istanbul, Turkey. oktarasoglu@yahoo.com
authors.forename: Oktar
authors.initials: O
authors.lastname: Asoglu
authors.forename: Hasan
authors.initials: H
authors.lastname: Karanlik
authors.forename: Mesut
authors.initials: M
authors.lastname: Parlak
authors.forename: Mustafa
authors.initials: M
authors.lastname: Kecer
authors.forename: Mahmut
authors.initials: M
authors.lastname: Muslumanoglu
authors.forename: Abdullah
authors.initials: A
authors.lastname: Igci
authors.forename: Vahit
authors.initials: V
authors.lastname: Ozmen
authors.forename: Mine
authors.initials: M
authors.lastname: Gulluoglu
authors.forename: Yersu
authors.initials: Y
authors.lastname: Kapran
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000556:secondary* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005743:Gastrectomy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D055815:Young Adult