title: Revisiting the concept of lymph node metastases of pancreatic head cancer: number of metastatic lymph nodes and lymph node ratio according to N stage.
abstract: BACKGROUND
  Some suggest that metastatic lymph node ratio (LNR) may be prognostic of survival in patients with pancreatic cancer. However, this phenomenon was confused by inclusion of node-negative patients in the analysis. The present study was designed to evaluate the prognostic impact of metastatic LNR and the absolute number of metastatic LNs in patients resected for pancreatic cancer.
  
  
  METHODS
  Data were collected from 398 patients who underwent curative surgery for pancreatic head cancer at Seoul National University Hospital. Long-term survival was analyzed according to LNR and absolute number of metastatic LNs.
  
  
  RESULTS
  Of the patients, 227 (57.0 %) had LN metastasis. The mean numbers of total retrieved and metastatic LNs were 19.5 and 1.9, respectively, and the mean LNR was 0.11. Median overall survival (OS) of patients was significantly higher in N0 than in N1 patients after curative resection (25.4 vs. 14.8 months, p < 0.001). Median OS was significantly lower in patients with 1 than in those with 0 positive LNs (17.3 vs. 25.4 months, p = 0.001). Among N1 patients, those with 0 < LNR ≤ 0.2 had comparable prognosis than those with >0.2 LNR (median OS 17.2 vs. 12.8 months, p = 0.096), and the number of metastatic LNs did not correlate with median OS (p = 0.365).
  
  
  CONCLUSIONS
  The presence of a single positive metastatic LN was associated with significantly poorer OS in patients with pancreatic cancer. When LN metastasis was present, the number of metastatic LNs and LNR had limited prognostic relevance.
authors.affiliation: Department of Surgery and Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Mee Joo
authors.initials: MJ
authors.lastname: Kang
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Ye Rim
authors.initials: YR
authors.lastname: Chang
authors.forename: Wooil
authors.initials: W
authors.lastname: Kwon
authors.forename: Woohyun
authors.initials: W
authors.lastname: Jung
authors.forename: Sun-Whe
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000556:secondary* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision / Q000401:mortality*; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate