title: Role of omentectomy as part of radical surgery for gastric cancer.
abstract: BACKGROUND
  A complete omentectomy is recommended as part of radical (sub)total gastrectomy for gastric cancer, but there is little evidence to suggest any survival benefit. The aim of this study was to evaluate the incidence of, and risk factors for, metastases in the greater omentum in patients undergoing gastrectomy for gastric cancer.
  
  
  METHODS
  This was a multicentre prospective cohort study (OMEGA trial) of consecutive patients with gastric cancer undergoing (sub)total gastrectomy with complete en bloc omentectomy and modified D2 lymphadenectomy. After resection, the omentum was separated from the gastrectomy specimen distal to the gastroepiploic vessels and sent separately for pathological examination. The primary endpoint was the presence of metastases in the greater omentum.
  
  
  RESULTS
  Of 100 included patients, five (5·0 per cent) had metastases in the greater omentum. Pathology results showed advanced tumours in all five (pT4b N1 M1, pT4b N2 M1, ypT4a N1 M1, ypT3 N2 M0, ypT3 N3 M0). The resection was microscopically non-radical at the proximal (3) or distal (2) resection margin in all of these patients. Metastases in the greater omentum correlated significantly with a microscopically non-radical resection, tumour expansion in the oesophagus or duodenum, linitis plastica or a proximal gastric tumour with diameter of at least 5 cm, stage III-IV disease and (y)pM1 category.
  
  
  CONCLUSIONS
  In resectable gastric cancer, the incidence of metastases in the greater omentum is low, and when present associated with advanced disease and non-radical features. Thus, omentectomy as part of a radical gastrectomy may be omitted.
  
  
  BACKGROUND
  NCT02050659 ( http://www.clinicaltrials.gov).
authors.affiliation: Departments of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: E J
authors.initials: EJ
authors.lastname: Jongerius
authors.affiliation: Departments of Surgery, St Antonius Hospital, Nieuwegein, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Boerma
authors.affiliation: Departments of Pathology, St Antonius Hospital, Nieuwegein, The Netherlands.
authors.forename: K A
authors.initials: KA
authors.lastname: Seldenrijk
authors.affiliation: Departments of Pathology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: S L
authors.initials: SL
authors.lastname: Meijer
authors.affiliation: Departments of Surgery, Reinier de Graaf Gasthuis, Delft, The Netherlands.
authors.forename: J J G
authors.initials: JJ
authors.lastname: Scheepers
authors.affiliation: Departments of Pathology, Reinier de Graaf Gasthuis, Delft, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: Smedts
authors.affiliation: Departments of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: S M
authors.initials: SM
authors.lastname: Lagarde
authors.affiliation: Departments of Pathology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: O
authors.initials: O
authors.lastname: Balague Ponz
authors.affiliation: Departments of Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: M I
authors.initials: MI
authors.lastname: van Berge Henegouwen
authors.affiliation: Departments of Surgery, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: van Sandick
authors.affiliation: Departments of Surgery, Academic Medical Centre, Amsterdam, The Netherlands. s.s.gisbertz@amc.nl.
authors.forename: S S
authors.initials: SS
authors.lastname: Gisbertz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061887:Conversion to Open Surgery / Q000706:statistics & numerical data; D005260:Female; D005743:Gastrectomy / Q000379:methods; D006801:Humans; D010535:Laparoscopy / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009852:Omentum / Q000601:surgery*; D011446:Prospective Studies; D013274:Stomach Neoplasms / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome