title: Impact of lymph node ratio on survival of colorectal cancer patients.
abstract: OBJECTIVE
  This study analyzed the prognostic significance of the staging system based on the metastatic Node Ratio (NR) compared with the TNM staging system in patients with colorectal cancer.
  
  
  METHODS
  We reviewed the data of 444 patients who underwent colorectal resection for cancer between January 2005 and December 2011. NR categories NR0 (0%), NR1 (1-19%) and NR2 (≥ 20%) were determined by the best cut-off approach at log-rank test. To compare the prognostic power of the NR versus pN, we plotted these different factors against the mortality estimates. Additionally, we evaluated the relationship between these variables and the extent of lymphadenectomy.
  
  
  RESULTS
  Both the NR and the pN classification significantly stratified patient outcomes (p < 0.0001), but the NR system seems to better discriminate prognostic subgroups than the pN. Furthermore, NR is less dependent on the extent of lymphadenectomy than pN.
  
  
  CONCLUSIONS
  NR is a simple and reliable tool to stratify survival of colorectal cancer patients and it seems to have a higher prognostic power than the current pN system, because it is less dependent on the extent of lymphadenectomy.
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Rausei
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Iovino
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Tenconi
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Mangano
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Inversini
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Boni
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Rovera
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Gianlorenzo
authors.initials: G
authors.lastname: Dionigi
authors.affiliation: Department of Surgical Sciences, University of Insubria, Varese, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Dionigi
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D016019:Survival Analysis
keywords: Lymph node ratio; Survival of colorectal cancer