title: Prognostic relevance of the lymph node ratio in surgical patients with extrahepatic cholangiocarcinoma.
abstract: OBJECTIVE
  Few studies have investigated the influence of the lymph node ratio (LNR), the ratio of the number of lymph nodes harboring metastatic cancer to the total number of lymph nodes removed, on the outcome after surgery for extrahepatic cholangiocarcinoma. This study was conducted to examine the prognostic impact of LNR in patients undergoing resection for extrahepatic cholangiocarcinoma.
  
  
  METHODS
  We retrospectively analyzed a total of 60 consecutive patients who underwent resection for extrahepatic cholangiocarcinoma. We focused on the LNR, which was classified as 0 in 34 patients, between 0 and 0.2 in 13 patients, and greater than 0.2 in 13 patients.
  
  
  RESULTS
  The overall five-year survival rates for patients with LNRs of 0, 0 to 0.2, and ≥0.2 were 44%, 10%, and 0%, respectively (p = 0.023). LNR was an independent predictive factor for estimated survival by both univariate (p = 0.016) and multivariate (p = 0.022) analyses including LNR, the sites of the primary tumors, and surgical margin as the variables. There were no statistically significant differences between patients who had less than 12 lymph nodes removed and those who had 12 or more lymph nodes removed (p = 0.484).
  
  
  CONCLUSIONS
  LNR was a powerful, independent predictor of estimated survival in patients undergoing surgical resection for extrahepatic cholangiocarcinoma. LNR should be considered when stratifying patients for future clinical trials.
authors.affiliation: Department of Surgery, University of Tsukuba, Graduate School of Comprehensive Human Sciences, 1-1-1 Tennodai, Tsukuba, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Oshiro
authors.forename: R
authors.initials: R
authors.lastname: Sasaki
authors.forename: A
authors.initials: A
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Murata
authors.forename: K
authors.initials: K
authors.lastname: Fukunaga
authors.forename: T
authors.initials: T
authors.lastname: Kondo
authors.forename: T
authors.initials: T
authors.lastname: Oda
authors.forename: N
authors.initials: N
authors.lastname: Ohkohchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000473:pathology* / Q000601:surgery; D018281:Cholangiocarcinoma / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis