Fluorescent imaging with indocyanine green as navigation surgery in robotic gastrectomy

Surgical R0 resection of the primary tumor and metastatic lymph nodes (LNs) is a mainstay in the treatment of gastric cancer (GC). We investigated the effectiveness of indocyanine green (ICG) imaging for (1) determining the resection margin of primary tumor and (2) identifying lymphatic flow of GC in robotic gastrectomy (RG). Between June 2019 and February 2022, 23 patients who consented to this prospective study and underwent radical RG with the diagnosis of gastric cancer were enrolled. For all patients, 0.6 ml of ICG (0.5mg/ml for first 7, 0.25mg/ml for the other 16) was administered submucosally at four locations around the tumor margins endoscopically the day before surgery. The endpoints were the safety of preoperative endoscopic ICG injection, postoperative short-term outcomes, distance of the resection margin and the status of ICG uptake in the regional LNs. In all 23 cases, there were no complications associated with preoperative endoscopic ICG administration. The 23 cases were as follows: cStageI/IIA/IIB/III/IVB=13/3/1/5/1, DG/PG/TG/CG=15/3/4/1, D1+/≧D2=12/11. The number of dissected lymph nodes was 46, blood loss was 0ml, and operation time was 416 min (all median). Clavien-Dindo grade3 postoperative complication (anastomotic bleeding) was observed in one patient. R0 resection was achieved in all cases with a pathological marginal distance of at least 10 mm. ICG uptake in nearby regional LNs was observed in all cases. Fluorescent imaging with ICG may help to determine the adequate resection margin in RG for GC.