Long-term Outcomes of Laparoscopic Versus Open Surgery for Clinical Stage i Gastric Cancer: The LOC-1 Study

Background: Clinical trials comparing laparoscopic gastrectomy (LG) versus traditional open gastrectomy (OG) have been planned, their surgical outcomes reported but their oncologic outcomes are still pending. Consequently, we have conducted this large-scale historical cohort study to provide relevant information rapidly to guide our current practice. Methods: Through a consensus meeting involving surgeons, biostatisticians, and epidemiologists, 30 variables of preoperative information possibly influencing surgeons' choice between LG versus OG and potentially associating with outcomes were identified to enable rigorous estimation of propensity scores. A total of 4235 consecutive patients who underwent gastrectomy for gastric adenocarcinoma were identified and their relevant data were gathered from the participating hospitals. After propensity score matching, 1848 patients (924 each for LG and OG) were selected for comparison of long-term outcomes. Results: In the propensity-matched population, the 5-year overall survival was 96.3% [95% confidence interval (CI) 95.0-97.6] in the OG as compared with 97.1% (95% CI, 95.9-98.3) in LG. The number of all-cause death was 33/924 in the OG and 24/924 in the LG through the entire period, and the hazard ratio (LG/OG) for overall death was 0.75 (95% CI, 0.44-1.27; P = 0.290). The 3-year recurrence-free survival was 97.4% (95% CI, 96.4-98.5) in the OG and 97.7% (95% CI, 96.5-98.8) in the LG. The number of recurrence was 22/924 in the OG and 21/924 in the LG through the entire period, and the hazard ratio was 1.01 (95% CI, 0.55-1.84; P = 0.981). Conclusions: This observational study adjusted for all-known confounding factors seems to provide strong enough evidence to suggest that LG is oncologically comparable to OG for gastric cancer.