Potential survival benefits of open over laparoscopic radical gastrectomy for gastric cancer patients beyond three years after surgery: result from multicenter in-depth analysis based on propensity matching

Background: The oncologic efficacy of laparoscopic versus open surgery for advanced distal gastric cancer (ADGC) beyond 3 years after surgery remain obscure. Methods: A total of 1256 patients with ADGC at two teaching institutions in China from April 2007 to December 2014 were enrolled. The general data of the two groups were identified to enable rigorous estimation of propensity scores. Restricted mean survival time (RMST) and Landmark analysis was used to compare survival. Results: After matching 461 patients each in the open distal gastrectomy (ODG) and laparoscopic distal gastrectomy (LDG) groups, they were included into analysis. The 3- and 5-year overall survival (OS) and disease-free survival were comparable in two groups. RMST-stratified analysis showed that the 3-year RMST of ODG group was similar to that of LDG group in patients with cT4a (− 1.38 years, p= 0.163) or with cT4a and tumor size > 5 cm, whereas the 5-year RMST had significant differences between groups in cT4a patients(− 8.36 years, P= 0.005) or cT4a and tumor size > 5 cm patients(4.67 years, P= 0.042). In patients with cT4a and tumors > 5 cm, the number of peritoneal recurrences was significantly fewer in the ODG group than in the LDG group (4 vs. 17, P= 0.033), and the peritoneal recurrence time and multiple-site recurrence time were both later in the ODG group. Conclusion: By reducing recurrence, ODG achieves a better survival for GC patients with serous infiltration and tumors larger than 5 cm beyond 3 years after surgery. The present findings can serve as a reference for surgical options and the setting of follow-up time point for clinical studies.