title: Preoperative chemotherapy does not influence the number of evaluable lymph nodes in resected gastric cancer.
abstract: BACKGROUND
  While it is suggested that more than 15 lymph nodes (LNs) should be evaluated for accurate staging of gastric cancer, LN yield in western countries is generally low. The effect of preoperative chemotherapy on LN yield in gastric cancer is unknown. The aim of the present study is to determine whether preoperative chemotherapy is associated with any difference in the number of LNs obtained from specimens of patients who underwent curative surgery for gastric adenocarcinoma.
  
  
  METHODS
  In 1205 patients from Memorial Sloan-Kettering Cancer Center (MSKCC) and 1220 patients from the Netherlands Cancer Registry (NCR) who underwent a gastrectomy with curative intent for gastric adenocarcinoma without receiving preoperative radiotherapy, LN yield was analyzed, comparing patients who received preoperative chemotherapy and patients who received no preoperative therapy.
  
  
  RESULTS
  Of the 2425 patients who underwent a gastrectomy, 14% received preoperative chemotherapy. Median LN yields were 23 at MSKCC and 10 in the NCR. Despite this twofold difference in LN yield between the two populations, with multivariate Poisson regression, chemotherapy was not associated with LN yield of either population. Variables associated with increased LN yield were institution, female sex, lower age, total (versus distal) gastrectomy and increasing T-stage.
  
  
  CONCLUSIONS
  In this patient series, treatment at MSKCC, female sex, lower age, total gastrectomy and increasing primary tumor stage were associated with a higher number of evaluated LNs. Preoperative chemotherapy was not associated with a decrease in LN yield. Evaluating more than 15 LNs after gastrectomy is feasible, with or without preoperative chemotherapy.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, United States. jdikken@gmail.com
authors.forename: J L
authors.initials: JL
authors.lastname: Dikken
authors.forename: N C T
authors.initials: NC
authors.lastname: van Grieken
authors.forename: P
authors.initials: P
authors.lastname: Krijnen
authors.forename: M
authors.initials: M
authors.lastname: Gönen
authors.forename: L H
authors.initials: LH
authors.lastname: Tang
authors.forename: A
authors.initials: A
authors.lastname: Cats
authors.forename: M
authors.initials: M
authors.lastname: Verheij
authors.forename: M F
authors.initials: MF
authors.lastname: Brennan
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: D G
authors.initials: DG
authors.lastname: Coit
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D000368:Aged; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D009426:Netherlands; D009519:New York City; D012042:Registries; D021701:Sentinel Lymph Node Biopsy; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome