Omentum-preserving gastrectomy for advanced gastric cancer: a propensity-matched retrospective cohort study

Background and objectives We clarified the impact of omentectomy for advanced gastric cancer on patient survival from the surgical results of a high-volume center in Japan. Methods Patients who received curative gastrectomy were divided into two groups based on whether they underwent omentectomy. The propensity score-matching method was used to assemble a well-balanced cohort, and relapse-free survival and the pattern of recurrence were compared. Results For this study, 330 patients who fulfilled the inclusion criteria participated and were divided into two groups: group R, patients who received omentectomy, and group P, patients who received omentum-preserving gastrectomy. After performing score-matching, 196 patients were selected. The 3- and 5-year relapse-free survival rates were 72.9 % (95 % confidence interval, 64.1–81.7) and 66.2 % (56.6–75.8 %) in group R, and 76.7 % (67.9–81.2) and 67.3 % (55.1–79.5) in group P, which were not significantly different ( P = 0.750). Regarding sites of relapses, no differences were observed between the groups ( P = 0.863). Conclusions In this series, omentum-preserving gastrectomy for advanced gastric cancer did not increase the peritoneal relapse rate or affect patient survival compared to conventional gastrectomy. The non-inferiority of the omission of omentectomy should be evaluated by a randomized controlled trial.