Indocyanine green fluorescence-guided proximal margin identification in laparoscopic distal gastrectomy: a randomized clinical trial

BACKGROUND: Achieving negative resection margins is critical in GC surgery, yet intraoperative tumor localization remains challenging, particularly in minimally invasive approaches such as LDG. This study was conducted to evaluate the safety, feasibility, and efficacy of indocyanine green (ICG) fluorescence imaging for real-time margin identification during laparoscopic distal gastrectomy (LDG) for gastric cancer (GC). METHODS: This randomized clinical trial included 422 patients with GC (cT1-4a, N0/+, M0) between September 2019 and December 2021, who underwent LDG with or without ICG fluorescence guidance. Oncological and perioperative outcomes were compared between the groups. RESULTS: The ICG group demonstrated a significantly lower rate of positive initial proximal margins (0% vs. 5.5%, P < 0.001) and reduced the need for total gastrectomy in middle third gastric cancer (0.5% vs. 3.8%, P = 0.037). In our study cohort, ICG guidance standardized resection margins (median 5.0 cm, IQR 3.8–5.6) with fewer deviations from guideline recommendations (P = 0.018). Pathological analysis confirmed the absence of tumor cells beyond 4 cm from the gross margin in our study cohort. The ICG group also had shorter operation times (217.60 ± 31.11 vs. 225.48 ± 27.69 min, P = 0.008) and fewer pulmonary complications (3.0% vs. 8.0%, P = 0.046). At 3-year follow-up, no significant survival difference was observed (DFS: 74.4% vs. 68.7%, P = 0.220; OS: 82.4% vs. 79.4%, P = 0.437). CONCLUSIONS: ICG fluorescence imaging improved margin accuracy, reduced non-indicated total gastrectomies, and enhanced operative efficiency. Its application in LDG provides a potential standardized strategy for achieving R0 resection.