title: Prognostic impact of the length of the longitudinal resection margin in colon cancer.
abstract: OBJECTIVE
  Although several guidelines recommend a longitudinal resection margin (LRM) of at least 5 cm, the impact of the LRM on survival is still unknown. The study assessed the prognostic significance of the LRM in patients with colon cancer.
  
  
  METHODS
  We retrospectively reviewed 1343 primary colon cancer patients without distant metastasis who underwent curative resection between January 2004 and December 2012. Patients were classified into three groups: LRM < 3 cm (n = 186), LRM ≥ 3 and <5 cm (n = 376) and LRM ≥5 cm (n = 781). Clinicopathological characteristics and the oncological outcome in the three groups were compared.
  
  
  RESULTS
  The median LRM length was 5.0 cm (range 0.5-26.0 cm). With increasing LRM, the number of retrieved lymph nodes (LNs) tended to increase (19.5 ± 12.0, 22.1 ± 12.8 and 30.0 ± 16.2; P < 0.001). After a median follow-up period of 45 (1-128) months, 3-year disease-free survival (DFS) (89.2%, 89.0% and 87.0%; P = 0.629) and 5-year overall survival (OS) (89.0%, 92.1% and 91.8%; P = 0.679) were not significantly different between the three groups. When confounders were adjusted, LRM was not significantly associated with either DFS or OS, but the number of retrieved LNs (< 12) was an independent risk factor for both DFS (hazard ratio 1.748, 95% confidence interval 1.048-2.917) and OS (hazard ratio 1.929, 95% confidence interval 1.046-3.559).
  
  
  CONCLUSIONS
  LRM was not associated with oncological outcome, but care should be taken to obtain an adequate number of LNs for better survival.
authors.affiliation: Department of Surgery, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Surgery, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Korea.
authors.forename: C H
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Surgery, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Korea.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Surgery, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Korea.
authors.forename: H R
authors.initials: HR
authors.lastname: Kim
mesh_terms: D000368:Aged; D003082:Colectomy / Q000379:methods*; D003110:Colonic Neoplasms / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D000072662:Margins of Excision; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Colon cancer; longitudinal resection margin; survival