title: Prognostic significance of the number of lymph node metastases in esophageal cancer.
abstract: BACKGROUND
  Regional lymph node (LN) involvement is one of the most important predictors of survival for patients with esophageal cancer. The current staging classification differentiates only between the presence and absence of LN metastasis. In this study, we examined whether involvement of a higher number of LNs is associated with worse survival among esophageal cancer patients.
  
  
  METHODS
  We identified all patients who underwent operations for node-positive esophageal cancer between 1988 and 2003 from the Surveillance, Epidemiology and End Results cancer registry. Because the number of positive LNs is confounded by the total number of LNs removed, patients were classified into three groups by the ratio of positive-to-total number of LNs removed (LN ratio [LNR]): <or= 0.2, 0.21 to 0.5, and>0.5. Esophageal cancer-specific survival was compared among these groups using Kaplan-Meier curves. Stratified and Cox regression analyses were used to evaluate the relationship between the LNR and survival after adjusting for potential confounders.
  
  
  RESULTS
  The study cohort included 838 esophageal cancer patients. Disease-specific survival rates decreased with higher LNR. Five-year disease-specific survival was 30% among patients with an LNR<or=0.2, compared with 16% and 13% for those with LNs of 0.21 to 0.5 and>0.5, respectively (p < 0.001). In stratified and multivariable analyses controlling for age, race, gender, histology, tumor-status, and postoperative radiotherapy, a higher LNR was independently associated with worse disease-specific survival.
  
  
  CONCLUSIONS
  These data suggest that a higher LNR among patients with node-positive esophageal cancer is associated with worse survival. If validated, this prognostic criterion may be included in staging classifications.
authors.affiliation: Department of General Surgery, Mount Sinai School of Medicine, New York, NY 10029, USA.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Greenstein
authors.forename: Virginia R
authors.initials: VR
authors.lastname: Litle
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Swanson
authors.forename: Celia M
authors.initials: CM
authors.lastname: Divino
authors.forename: Stuart
authors.initials: S
authors.lastname: Packer
authors.forename: Juan P
authors.initials: JP
authors.lastname: Wisnivesky
mesh_terms: D000368:Aged; D015331:Cohort Studies; D004938:Esophageal Neoplasms / Q000401:mortality* / Q000556:secondary* / Q000628:therapy; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D018426:SEER Program; D015996:Survival Rate; D014481:United States / Q000453:epidemiology