title: Evaluation of lymph node numbers for adequate staging of Stage II and III colon cancer.
abstract: BACKGROUND
  Although evaluation of at least 12 lymph nodes (LNs) is recommended as the minimum number of nodes required for accurate staging of colon cancer patients, there is disagreement on what constitutes an adequate identification of such LNs.
  
  
  METHODS
  To evaluate the minimum number of LNs for adequate staging of Stage II and III colon cancer, 490 patients were categorized into groups based on 1-6, 7-11, 12-19, and ≥ 20 LNs collected.
  
  
  RESULTS
  For patients with Stage II or III disease, examination of 12 LNs was not significantly associated with recurrence or mortality. For Stage II (HR = 0.33; 95% CI, 0.12-0.91), but not for Stage III patients (HR = 1.59; 95% CI, 0.54-4.64), examination of ≥20 LNs was associated with a reduced risk of recurrence within 2 years. However, examination of ≥20 LNs had a 55% (Stage II, HR = 0.45; 95% CI, 0.23-0.87) and a 31% (Stage III, HR = 0.69; 95% CI, 0.38-1.26) decreased risk of mortality, respectively. For each six additional LNs examined from Stage III patients, there was a 19% increased probability of finding a positive LN (parameter estimate = 0.18510, p < 0.0001). For Stage II and III colon cancers, there was improved survival and a decreased risk of recurrence with an increased number of LNs examined, regardless of the cutoff-points. Examination of ≥7 or ≥12 LNs had similar outcomes, but there were significant outcome benefits at the ≥20 cutoff-point only for Stage II patients. For Stage III patients, examination of 6 additional LNs detected one additional positive LN.
  
  
  CONCLUSIONS
  Thus, the 12 LN cut-off point cannot be supported as requisite in determining adequate staging of colon cancer based on current data. However, a minimum of 6 LNs should be examined for adequate staging of Stage II and III colon cancer patients.
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: Chandrakumar
authors.initials: C
authors.lastname: Shanmugam
authors.forename: Robert B
authors.initials: RB
authors.lastname: Hines
authors.forename: Nirag C
authors.initials: NC
authors.lastname: Jhala
authors.forename: Venkat R
authors.initials: VR
authors.lastname: Katkoori
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: James A
authors.initials: JA
authors.lastname: Posey
authors.forename: Harvey L
authors.initials: HL
authors.lastname: Bumpers
authors.forename: William E
authors.initials: WE
authors.lastname: Grizzle
authors.forename: Isam E
authors.initials: IE
authors.lastname: Eltoum
authors.forename: Gene P
authors.initials: GP
authors.lastname: Siegal
authors.forename: Upender
authors.initials: U
authors.lastname: Manne
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging; D016896:Treatment Outcome