title: Utility of the proximal margin frozen section for resection of gastric adenocarcinoma: a 7-Institution Study of the US Gastric Cancer Collaborative.
abstract: BACKGROUND
  The proximal gastric margin dictates the extent of resection for gastric adenocarcinoma (GAC). The value of achieving negative margins via additional gastric resection after a positive proximal margin frozen section (FS) is unknown.
  
  
  METHODS
  The US Gastric Cancer Collaborative includes all patients who underwent resection of GAC at seven institutions from 2000-2012. Intraoperative proximal margin FS data and final permanent section (PS) data were classified as R0 or R1, respectively; positive distal margins were excluded. The primary aim was to evaluate the impact on local recurrence of converting a positive proximal FS-R1 margin to a PS-R0 final margin by additional resection. Secondary endpoints were recurrence-free survival (RFS) and overall survival (OS).
  
  
  RESULTS
  Of 860 patients, 520 had a proximal margin FS and 67 were positive. Of these, 48 were converted to R0 on PS by additional resection. R0 proximal margin was achieved in 447 patients (86 %), PS-R1 in 25 (5 %), and converted FS-R1-to-PS-R0 in 48 (9 %). The median follow-up was 44 months. Local recurrence was significantly decreased in the converted FS-R1-to-PS-R0 group compared to the PS-R1 group (10 vs. 32 %; p = 0.01). Median RFS was similar between the FS-R1-to-PS-R0 and PS-R1 cohorts (25 vs. 20 months; p = 0.49), compared to 37 months for the PS-R0 group. Median OS was similar between the FS-R1-to-PS-R0 conversion and PS-R1 groups (36 vs. 26 months; p = 0.14) compared to 50 months for the PS-R0 group. On multivariate analysis, increasing T-stage and N-stage were associated with worse OS; the FS-R1-to-PS-R0 proximal margin conversion was not significantly associated with improved RFS (p = 0.68) or OS (p = 0.44).
  
  
  CONCLUSIONS
  Conversion of a positive intraoperative proximal margin frozen section during gastric cancer resection may decrease local recurrence, but it is not associated with improved RFS or OS. This may guide decisions regarding the extent of resection.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Winship Cancer Institute, Emory University, Atlanta, GA, USA.
authors.forename: Malcolm H
authors.initials: MH
authors.lastname: Squires
authors.forename: David A
authors.initials: DA
authors.lastname: Kooby
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Pawlik
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Weber
authors.forename: George
authors.initials: G
authors.lastname: Poultsides
authors.forename: Carl
authors.initials: C
authors.lastname: Schmidt
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Votanopoulos
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Fields
authors.forename: Aslam
authors.initials: A
authors.lastname: Ejaz
authors.forename: Alexandra W
authors.initials: AW
authors.lastname: Acher
authors.forename: David J
authors.initials: DJ
authors.lastname: Worhunsky
authors.forename: Neil
authors.initials: N
authors.lastname: Saunders
authors.forename: Linda X
authors.initials: LX
authors.lastname: Jin
authors.forename: Edward
authors.initials: E
authors.lastname: Levine
authors.forename: Clifford S
authors.initials: CS
authors.lastname: Cho
authors.forename: Mark
authors.initials: M
authors.lastname: Bloomston
authors.forename: Emily
authors.initials: E
authors.lastname: Winslow
authors.forename: Kenneth
authors.initials: K
authors.lastname: Cardona
authors.forename: Charles A
authors.initials: CA
authors.lastname: Staley
authors.forename: Shishir K
authors.initials: SK
authors.lastname: Maithel
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D000368:Aged; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005629:Frozen Sections / Q000706:statistics & numerical data*; D005743:Gastrectomy / Q000401:mortality*; D006801:Humans; D008197:Lymph Node Excision / Q000401:mortality*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D009367:Neoplasm Staging; D011379:Prognosis; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D015996:Survival Rate; D014481:United States