Omentectomy as Part of Radical Surgery for Gastric Cancer: 5-Year Follow-Up Results of a Multicenter Prospective Cohort Study

Introduction: Curative therapy for gastric cancer usually consists of perioperative chemotherapy combined with a radical (R0) gastrectomy. In addition to a modified D2 lymphadenectomy, a complete omentectomy is recommended. However, there is little evidence for a survival benefit of omentectomy. This study presents the follow-up data of the OMEGA study. Methods: This multicenter prospective cohort study included 100 consecutive patients with gastric cancer undergoing (sub)total gastrectomy with complete en bloc omentectomy and modified D2 lymphadenectomy. Primary outcome of the current study was 5-year overall survival. Patients with or without omental metastases were compared. Pathological factors associated with locoregional recurrence and/or metastases were tested with multivariable regression analysis. Results: Of 100 included patients, five had metastases in the greater omentum. Five-year overall survival was 0.0% in patients with omental metastases and 44.2% in patients without omental metastases (p = 0.001). Median overall survival time for patients with or without omental metastases was 7 months and 53 months. A (y)pT3-4 stage tumor and vasoinvasive growth were associated with locoregional recurrence and/or metastases in patients without omental metastases. Conclusion: The presence of omental metastases in gastric cancer patients who underwent potentially curative surgery was associated with impaired overall survival. Omentectomy as part of radical gastrectomy for gastric cancer might not contribute to a survival benefit in case of undetected omental metastases.