title: Systematic review of the predictors of positive margins in gastric cancer surgery and the effect on survival.
abstract: BACKGROUND
  Complete resection is the only definitive treatment available for gastric cancer. Factors associated with positive margins and their survival effects have been the subject of many studies, but the appropriate management for these patients is still debated. The objective of this review is to examine positive margins after gastric cancer resections by exploring predictive factors, impact on survival, and optimal strategies for re-resection.
  
  
  METHODS
  A systematic electronic literature search was conducted using Medline and EMBASE from January 1, 1998, to December 31, 2009. Studies on gastric or gastroesophageal junction adenocarcinoma that either investigated the predictors for positive margin or employed multivariate methods to analyze the survival effects of positive margins were selected.
  
  
  RESULTS
  Twenty-two studies incorporating 19355 patients were included in this review. Positive margins were associated with larger tumor size, deeper wall penetration, more extensive gastric involvement, greater nodal involvement, higher stage, diffuse histology, higher Borrmann type, lymphatic vessel involvement, and total gastrectomy. Patient survival was independently associated with margin status, and this survival effect was more prominent in early cancers in most studies that performed subgroup analyses.
  
  
  CONCLUSIONS
  The probability of acquiring positive margins is highly dependent on the biology and the extent of the tumor. There is a significant negative effect on survival, which is more prominent in cancers at early stages, making re-resection or a second operation important. Patients with more advanced disease can be offered more extensive surgery to remove disease, but this should be balanced against the risks of more extensive resections.
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Canada.
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Raziee
authors.forename: Roberta
authors.initials: R
authors.lastname: Cardoso
authors.forename: Rajini
authors.initials: R
authors.lastname: Seevaratnam
authors.forename: Alyson
authors.initials: A
authors.lastname: Mahar
authors.forename: Lucy
authors.initials: L
authors.lastname: Helyer
authors.forename: Calvin
authors.initials: C
authors.lastname: Law
authors.forename: Natalie
authors.initials: N
authors.lastname: Coburn
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000601:surgery*; D004938:Esophageal Neoplasms / Q000473:pathology / Q000601:surgery; D004943:Esophagogastric Junction / Q000473:pathology / Q000601:surgery; D005743:Gastrectomy / Q000379:methods*; D006801:Humans; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D013274:Stomach Neoplasms / Q000473:pathology / Q000601:surgery*; D016019:Survival Analysis; D016896:Treatment Outcome