title: The prognostic value of the number of lymph nodes removed in patients with node-negative colorectal cancer.
abstract: BACKGROUND
  To investigate the prognostic significance of the number of lymph nodes removed in colorectal cancer (CRC) patients with no metastatic lymph node.
  
  
  METHODS
  The clinicopathological data of 461 CRC patients was analyzed. In order to compare the survival of patients who had fewer lymph nodes removed versus the survival of patients who had 1-3 metastatic lymph node(s), a separate group of 74 N1 disease patients were also included in the study. All patient data were collected prospectively. Kaplan-Meier method was used for calculation and plotting of the survival curves of the patient groups, and log-rank test was used for the comparison of the survival curves.
  
  
  RESULTS
  Cancer-specific survival (CSS) rates of patients who had 1-7 lymph node(s) and 8-11 lymph nodes removed were significantly worse than those who had 12 or more lymph nodes removed (p = 0.006 and p = 0.037, respectively), while CSS was not significantly different between those who had 1-7 versus 8-11 lymph node(s) removed (p = 0.647); this grouping had independent prognostic significance in Cox analysis (p = 0.006). CSS of patients with N1 disease was not significantly different from those who had 1-7 and 8-11 lymph node(s) removed (p = 0.312 and p = 0.165, respectively), while it was significantly worse than CSS of patients who had 12 or more lymph nodes removed (p = 0.001).
  
  
  CONCLUSIONS
  In colorectal cancer patients whose removed lymph nodes are non-metastatic, removal of at least 12 lymph nodes will determine the lymph node status reliably.
authors.affiliation: Department of Surgery, SB Okmeydanı Training and Research Hospital, İstanbul, Turkey. Electronic address: nuvitduraker@gmail.com.
authors.forename: Nüvit
authors.initials: N
authors.lastname: Duraker
authors.affiliation: Department of Surgery, Bayındır Levent Hospital, İstanbul, Turkey.
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Civelek Çaynak
authors.affiliation: Department of Surgery, SB Okmeydanı Training and Research Hospital, İstanbul, Turkey.
authors.forename: Semih
authors.initials: S
authors.lastname: Hot
mesh_terms: D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000401:mortality* / Q000706:statistics & numerical data; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D009367:Neoplasm Staging; D011379:Prognosis; D015996:Survival Rate
keywords: Lymph node number; Node-negative colorectal cancer; Survival