title: A high lymph node yield in colon cancer is associated with age, tumour stage, tumour sub-site and priority of surgery. Results from a prospective national cohort study.
abstract: OBJECTIVE
  To determine the relation between patient-related and histopathological factors, as well as the influence of national programs for diagnosing and treatment of colon cancer and a lymph node yield (LNY) ≥ 12.
  
  
  METHODS
  An analysis was carried out of the LNY in a nationwide Danish cohort treated by curative resection of stage I-III colon cancer in the period 2003-2011. The association between a LNY ≥ 12 and age, sex, body mass index, open vs. laparoscopic surgery, acute vs. elective surgery, pT stage, tumour sub-site and year of diagnosis was analysed.
  
  
  RESULTS
  A total of 13,766 patients were eligible for the analysis. In total, 71.4 % of the patients had a LNY ≥ 12. In multivariate analysis, age, pT stage, tumour sub-site and priority of surgery were independently associated with the probability of a LNY ≥ 12. Odds ratios (ORs) were as follows: age <65 1, 65-75 0.685 (confidence interval (CI) 0.586-0.800), >75 0.517 (CI 0.439-0.609); T1 1, T2 2.750 (CI 2.168-3.487), T3 6.016 (CI 4.879-7.418), T4 6.317 (CI 4.950-8.063); right colon 1, left colon 0.568 (0.511-0.633); elective surgery 1, acute surgery 0.748 (CI 0.625-0.894). Moreover, year of diagnosis was associated with the probability of a LNY ≥ 12: OR 1.480 (CI 1.445-1.516) for each increasing year in the study period.
  
  
  CONCLUSIONS
  A LNY ≥ 12 is significantly associated with age, pT stage, tumour sub-site and priority of surgery. A significant increase in the LNY over the period of the study was observed, probably reflecting the effect of national programmes initiated by the Danish Colorectal Cancer Group.
authors.affiliation: Department of Surgery, Herlev Hospital, University of Copenhagen, Herlev, Denmark. jaklyk@gmail.com.
authors.forename: Jakob
authors.initials: J
authors.lastname: Lykke
authors.affiliation: Department of Surgery, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Jess
authors.affiliation: Department of Surgery, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Roikjær
mesh_terms: D000367:Age Factors; D000368:Aged; D003110:Colonic Neoplasms / Q000473:pathology* / Q000601:surgery*; D003718:Denmark; D005260:Female; D006801:Humans; D016015:Logistic Models; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies
keywords: Colon cancer; Lymph node yield; Lymph nodes; National guidelines