Omentum preservation as an oncologically comparable and surgically superior alternative to total omentectomy during radical gastrectomy for T3–T4 gastric cancer

Background: Total omentectomy has conventionally been performed and has been regarded as standard procedure in radical gastrectomy for cancer. However, omentum preservation is the preferred procedure during minimally invasive surgery, without sufficient evidence of oncological safety, especially for T3–T4 gastric cancer. Method: A total of 3,510 patients who underwent radical gastrectomy for T3–T4 gastric cancer between January 2003 and December 2015 were reviewed, retrospectively. After propensity score matching, 225 patients in the omentum preservation group were compared with 225 patients in the total omentectomy group. The primary outcome was 5-year overall survival. Results: The omentum preservation group showed significantly shorter operation time (P = .001) and less blood loss (P = .004) than the total omentectomy group. Shorter operation time was also observed with both open and minimally invasive approaches (P < .001 and P = .007, respectively). The 5-year overall survival rates were 75.4% for the omentum preservation group and 72.6% for the total omentectomy group (log-rank P = .06; hazard ratio 0.7 [95% confidence interval, 0.48–1.01]). The 5-year relapse-free survival was higher in the omentum preservation group (73.8%) than in the total omentectomy group (66.1%), without statistical significance (log-rank P = .09; hazard ratio 0.74 [95% confidence interval, 0.52–1.06]). Conclusion: Regardless of the surgical approach, omentum preservation provided comparable oncologic outcomes with better surgical outcomes, suggesting that this could be an acceptable alternative to total omentectomy for T3–T4 gastric cancer. These findings warrant further investigation in randomized clinical trials.