title: Lymph node retrieval in colorectal cancer: determining factors and prognostic significance.
abstract: OBJECTIVE
  The study aimed to analyze clinicopathological factors that determine the extent of lymph node retrieval and to evaluate its prognostic impact in patients with colorectal cancer (CRC).
  
  
  METHODS
  The number of retrieved lymph nodes was analyzed in 381 CRC specimens. Lymph node count was related to different clinicopathological variables by binary logistic regression. Progression-free survival (PFS) and cancer-specific survival (CSS) were determined using the Kaplan-Meier method and Cox regression models.
  
  
  RESULTS
  The median number of retrieved lymph nodes was 20 (mean 21 ± 10, range 1-65) in right-sided, 13 (16 ± 10, 1-66) in left-sided, and 15 (18 ± 11, 3-64) in rectal tumors. The number of retrieved lymph nodes was independently associated with T-classification (p < 0.001), N-classification (p = 0.014), and tumor size (p = 0.005) as well as right-sided tumor location (p = 0.012). There was no association with age, sex, tumor grade, mismatch-repair status, and lymph or blood vessel invasion. The longer the surgical specimen, the higher were the numbers of retrieved and positive lymph nodes (p < 0.001, respectively). In patients with locally advanced (T3/T4) tumors (n = 283), analysis of more than 12 lymph nodes was independently associated with PFS (HR = 0.63, p = 0.025) and CSS (HR = 0.54, p = 0.004). In the subset of T3/T4 N0 patients (n = 130), analysis of more than 12 lymph nodes similarly proved to be an independent predictor of outcome (PFS, HR = 0.48, p = 0.046; OS, HR = 0.41, p = 0.026).
  
  
  CONCLUSIONS
  The number of retrieved lymph nodes is associated with higher tumor stage, tumor size, and right-sided location. Low lymph node count indicates adverse outcome in patients with locally advanced (T3/T4) disease.
authors.affiliation: Department of Medicine II, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Betge
authors.affiliation: Department of Medicine II, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Harbaum
authors.affiliation: Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria.
authors.forename: Marion J
authors.initials: MJ
authors.lastname: Pollheimer
authors.affiliation: Department of Surgery, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Lindtner
authors.affiliation: Department of Surgery, Division of General Surgery, Medical University of Graz, Graz, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Kornprat
authors.affiliation: Department of Medicine II, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
authors.forename: Matthias P
authors.initials: MP
authors.lastname: Ebert
authors.affiliation: Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria. cord.langner@medunigraz.at.
authors.forename: Cord
authors.initials: C
authors.lastname: Langner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D016015:Logistic Models; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016019:Survival Analysis
keywords: Colon cancer; Lymph node; Multivariate analysis; Prognostic factor; Rectum cancer