Prospective Feasibility Study of Laparoscopic and Robotic Distal Gastrectomy for Advanced Gastric Cancer to Verify the Safety of Surgical Proximal Margins

ABSTRACT Ensuring an adequate surgical proximal margin (SPM) is crucial in radical gastrectomy for gastric cancer. However, the lack of tactile feedback in laparoscopic distal gastrectomy (LDG) and robotic distal gastrectomy (RDG) poses challenges in precisely determining tumor boundaries, particularly in advanced gastric cancer, where tumor infiltration may extend beyond endoscopically detectable margins. This single‐center prospective study evaluates the safety of SPM in LDG and RDG for advanced gastric cancer. Methods Patients with cT1N2–3/cT2N0–3/cT3‐4aN0 gastric cancer were enrolled. The primary endpoint was the incidence of SPM < 20 mm. The planned sample size was 130, providing 90% power under the hypothesis of an expected incidence of 10% and a threshold of 20%, using an exact binomial test at a 5% one‐sided significance level. Results Between December 2017 and December 2021, 130 eligible patients were enrolled. Among them, 32 (24.6%) underwent RDG, and 5 (3.8%) required conversion to open surgery. The median SPM length was 52 mm (IQR: 40–76 mm). The incidence of SPM < 20 mm was 3.1% (4/130; 95% CI, 0%–6.9%), below the predefined threshold of 20% and predicted value of 10%. Two patients (1.5%) had positive margins. The overall complication rate was 10.4%, with intra‐abdominal infectious complications occurring in 3.1%. No Clavien–Dindo grade IVA or higher complications were observed. Conclusions LDG and RDG can achieve a safe SPM in advanced gastric cancer, with a low incidence of SPM < 20 mm, ensuring a very low risk of positive SPM.