title: Clinico-pathological factors influencing lymph node yield in colorectal cancer and impact on survival: analysis of New Zealand Cancer Registry data.
abstract: BACKGROUND
  Lymph node yield (LNY) and lymph node ratio (LNR) are recognized as independent prognostic factors in colorectal cancer (CRC).
  
  
  OBJECTIVE
  To examine the relationship between LNY and other clinico-pathological variables, and the prognostic value of LNY and LNR on patient survival in CRC.
  
  
  METHODS
  The clinico-pathological and survival data for patients diagnosed from January 2000 to July 2012 were retrieved from the New Zealand Cancer Registry. Multiple linear regression was used to identify clinico-pathological factors influencing LNY, and Cox regression was used to determine the association between LNY and LNR and patient survival.
  
  
  RESULTS
  14,646 patients were included in the study (mean age 70.3 years, 50.1% male). Mean LNY was 17.4. Younger age, right-sided disease, higher T stage, female sex and no neoadjuvant radiotherapy (rectal cancer) were all associated with higher LNY (P ≤ 0.001). Overall survival in Stage I-III disease increased with higher LNY (for LNY ≥ 12, HR = 0.67, 95% CI 0.64-0.72; P < 0.001). Survival in Stage III-IV disease was inversely related to LNR (HR = 0.56, 95% CI 0.51-0.62; P < 0.001).
  
  
  CONCLUSIONS
  LNY is influenced by patient age, site of disease and T stage. LNY (Stage I-II) and LNR (Stage III-IV) have independent prognostic value in CRC.
authors: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Department of Anatomy, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors: Omid
authors: O
authors: Ahmadi
authors: Mark D
authors: MD
authors: Stringer
authors: Michael A
authors: MA
authors: Black
authors: John L
authors: JL
authors: McCall
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology; D000367:Age Factors; D000368:Aged; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008197:Lymph Node Excision / Q000706:statistics & numerical data*; D008207:Lymphatic Metastasis; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D011379:Prognosis; D012042:Registries; D012737:Sex Factors
keywords: colon cancer; prognosis; rectal cancer