title: Lymphadenectomy in the staging and treatment of intrahepatic cholangiocarcinoma: a population-based study using the National Cancer Institute SEER database.
abstract: OBJECTIVE
  Although lymphatic spread is common in intrahepatic cholangiocarcinoma (ICC), lymphadenectomy is not widely performed as part of operative resection in this disease. The objectives of this study were to assess national trends for lymphadenectomy and its impact on survival in patients with ICC.
  
  
  METHODS
  The National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) registry was queried to identify patients with ICC (n=4893) reported during 1988-2007. Kaplan-Maier and Cox proportional hazards regression were used to analyse survival.
  
  
  RESULTS
  Five-year overall survival (OS) was 5.2%. Lymph node (LN) status was available for 48.9% (n=2391) of patients. Histologic LN evaluation was performed in 13.5% (n=658) of patients for a median of two (interquartile range: 1-3) LNs. During the study period, the frequency of histologic LN assessment (P=0.78) did not change in liver resection patients. In the 733 resected patients, positive vs. negative LN status was associated with worse 5-year OS of 8.4% vs. 25.9%, respectively (hazard ratio=1.8; P<0.001).
  
  
  CONCLUSIONS
  Nodal status is an important prognostic factor for survival in patients diagnosed with ICC. In the USA, few patients undergo hepatic resection with lymphadenectomy; therefore, the clinical benefit of formal lymphadenectomy in ICC remains unknown.
authors.affiliation: Division of Gastroenterology and General Surgery, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Clancy J
authors.initials: CJ
authors.lastname: Clark
authors.forename: Christina M
authors.initials: CM
authors.lastname: Wood-Wentz
authors.forename: Kaye M
authors.initials: KM
authors.lastname: Reid-Lombardo
authors.forename: Michael L
authors.initials: ML
authors.lastname: Kendrick
authors.forename: Marianne
authors.initials: M
authors.lastname: Huebner
authors.forename: Florencia G
authors.initials: FG
authors.lastname: Que
mesh_terms: D000368:Aged; D001650:Bile Duct Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D001653:Bile Ducts, Intrahepatic / Q000473:pathology* / Q000601:surgery*; D018281:Cholangiocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006498:Hepatectomy / Q000401:mortality / Q000639:trends; D006801:Humans; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D016015:Logistic Models; D008197:Lymph Node Excision / Q000401:mortality / Q000639:trends; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016017:Odds Ratio; D018579:Patient Selection; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D018426:SEER Program; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States