title: Lymph node examination among patients with gastric cancer: variation between departments of pathology and prognostic impact of lymph node ratio.
abstract: BACKGROUND
  At least 15 lymph nodes should be retrieved for proper TNM-staging in gastric cancer. We evaluated nodal harvest and examined its relation to stage distribution and survival at a population-based level, including the value of N-ratio (metastatic/evaluated) as a staging modality.
  
  
  METHODS
  All patients resected for primary M0 gastric cancer diagnosed in 1999-2007 in the Dutch Eindhoven Cancer Registry area were included (N = 880). Determinants of lymph node evaluation and their relationship with stage and survival were assessed in multivariable regression analyses. N-ratio categories were determined (N-ratio 0, 0%; N-ratio 1, 0.1%-19%; N-ratio 2, 20%-29%; N-ratio 3, ≥30%)
  
  
  RESULTS
  The median number of lymph nodes examined was 7, dependent on N-category (N0: 7; N+: 8). It varied between departments of pathology from 5 to 9. This variation remained after adjustment for relevant patient- and tumour factors. Stage distribution differed between pathology departments (proportion N0 ranging from 14% to 21%, p = 0.003). Among resected patients with N0M0 disease and <7 nodes examined, 5-year survival was 56%, compared to 69% among patients with ≥7 nodes examined (p = 0.012). Five-year survival for N-ratio 0 was 58%, N-ratio 1 50%, N-ratio 2 18% and N-ratio 3 11% (p < 0.0001), while 5-year survival ranged from 58% for N0, 17% for N1, and 11% for N2/3 (p < 0.0001).
  
  
  CONCLUSIONS
  In this series of patients with a relatively low number of evaluated lymph nodes, a high prognostic accuracy of N-ratio was found. However, improvement in nodal assessment is mandatory.
authors: Comprehensive Cancer Centre South , Department of Research, 5600 AE Eindhoven, The Netherlands. v.lemmens@ikz.nl
authors: V E P P
authors: VE
authors: Lemmens
authors: A E
authors: AE
authors: Dassen
authors: A A M
authors: AA
authors: van der Wurff
authors: J W W
authors: JW
authors: Coebergh
authors: K
authors: K
authors: Bosscha
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D005743:Gastrectomy; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D009426:Netherlands / Q000453:epidemiology; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D012042:Registries; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D016019:Survival Analysis