title: The prognostic value of lymph node ratio in colon cancer is independent of resection length.
abstract: BACKGROUND
  Lymph node ratio (LNR), the ratio of tumor-positive lymph nodes (+LN) to the total number of resected lymph nodes (rLN), predicts recurrence and survival in colon cancer. Variations in colonic resection length (RL) may influence rLN, +LN, or both, thereby potentially impacting LNR and its prognostic value in colon cancer.
  
  
  METHODS
  All colon cancer patients treated surgically at our center from 2004 to 2011 were included in an institutional review board-approved data repository (n = 1,039).
  
  
  RESULTS
  Larger RL was associated with increased rLN (ρ = .22; P < .001) but not with +LN (P = .21). In node-positive patients (n = 411), RL-adjusted LNR had weaker correlations with death (ρ = .338 vs .373, both P < .001) or metastatic disease (ρ = .303 vs .345; both P < .001) and a smaller area under the curve (death: .695 vs .715, metastasis: .675 vs .699). Findings were similar in segmental, extended segmental, and total colectomy subgroups.
  
  
  CONCLUSIONS
  Provided that resections are performed following standard oncologic principles, our analysis shows that RL does not significantly impact the prognostic value of LNR in colon cancer. Correcting LNR for RL seems redundant and may even act as noise distorting LNR values.
authors.affiliation: Division of General and Gastrointestinal Surgery, Massachusetts General Hospital, Harvard Medical School, 15 Parkman St, WAC 460, Boston, MA 02114, USA.
authors.forename: Ramzi
authors.initials: R
authors.lastname: Amri
authors.affiliation: Section of Colon and Rectal Surgery, Department of Surgery, Washington University School of Medicine, Saint Louis, MO, USA.
authors.forename: Coen L
authors.initials: CL
authors.lastname: Klos
authors.affiliation: Division of General and Gastrointestinal Surgery, Massachusetts General Hospital, Harvard Medical School, 15 Parkman St, WAC 460, Boston, MA 02114, USA.
authors.forename: Liliana
authors.initials: L
authors.lastname: Bordeianou
authors.affiliation: Division of General and Gastrointestinal Surgery, Massachusetts General Hospital, Harvard Medical School, 15 Parkman St, WAC 460, Boston, MA 02114, USA. Electronic address: dberger@mgh.harvard.edu.
authors.forename: David L
authors.initials: DL
authors.lastname: Berger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy / Q000379:methods; D003106:Colon / Q000473:pathology / Q000601:surgery*; D003110:Colonic Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis
keywords: Colon cancer; Disease-free survival; Lymph node ratio; Outcomes; Resection length; Survival