title: Significant regional variation in adequacy of lymph node assessment and survival in gastric cancer.
abstract: BACKGROUND
  Lymph node (LN) status is a major determinant of prognosis and treatment of gastric adenocarcinoma. The 1997 American Joint Commission on Cancer/Union Internationale Contre le Cancer guidelines were revised, requiring examination of > or =15 LN for staging.
  
  
  METHODS
  We investigated compliance with these guidelines and the correlation with overall survival (OS) by analyzing 10,807 resected gastric cancers in the Surveillance, Epidemiology and End Results (SEER) database, 1988-2002. Kaplan-Meier survival curves were constructed; survival was compared by using Cox proportional hazards.
  
  
  RESULTS
  Overall, 29% of cases had > or =15 LN examined. After 1997, the median number of LN assessed increased from 9 to 10 (P < .0001). Factors predictive of adequate LN assessment (ALNA) were higher stage, worse grade, age <74 years, later year of diagnosis, nonwhite race, more extensive surgery, female sex, and SEER region. Differences in the rate of ALNA between regions were noted, ranging from 19.7-53% (P < .0001). Of T1N0 patients, 19% had ALNA. Improved OS was predicted by earlier stage, lower grade, marital status, Asian race, younger age, T-stage, female sex, SEER region, and ALNA. Median OS was highest in the region with the best ALNA rate and worst in the region with the lowest (33 mos vs. 17 mos, P < .0001). Inadequate LN assessment led to poorer survival at every stage (P < .001).
  
  
  CONCLUSIONS
  The overwhelming majority of patients have an inadequate LN assessment. ALNA was associated with improved OS, with significant variation across regions. Understaging due to inadequate LN assessment may affect eligibility for adjuvant therapy. Education is required to improve LN retrieval.
authors.affiliation: Division of Surgical Oncology, Toronto Sunnybrook Regional Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada. natalie.coburn@sunnybrook.ca
authors.forename: Natalie G
authors.initials: NG
authors.lastname: Coburn
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Swallow
authors.forename: Alex
authors.initials: A
authors.lastname: Kiss
authors.forename: Calvin
authors.initials: C
authors.lastname: Law
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003710:Demography; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D008197:Lymph Node Excision / Q000706:statistics & numerical data; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000592:standards*; D016016:Proportional Hazards Models; D018426:SEER Program; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000401:mortality* / Q000473:pathology; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology