Impact of indocyanine green on nodal dissection and staging for gastric cancer surgery: iGreenGO prospective multicentre study

Background Lymphadenectomy is critical for accurate staging and prognostication of advanced gastric cancer. Indocyanine green (ICG) fluorescence imaging may optimize lymph node dissection but its applicability in Western patients is unclear. The aim of this study was to evaluate whether intraoperative ICG fluorescence is associated with change in surgical conduct (CSC) and stage migration during gastrectomy. Methods This was a prospective, multicentre observational study (iGreenGO) conducted at 15 Italian referral centres. Patients with cT2-4a N0-3 M0 gastric adenocarcinoma undergoing minimally invasive distal or total gastrectomy with D2 lymphadenectomy were eligible. Endoscopic peritumoral ICG injection (2 ml at a concentration of 0.125 mg/ml) was performed within 20 h before surgery. The primary outcome was CSC, defined as additional tissue dissection prompted by residual fluorescence after standard white-light D2 lymphadenectomy. Results A total of 316 patients (median age of 71.2 years; 185 male) were included between January 2022 and December 2024. The median number of dissected lymph nodes was 38 (interquartile range 29-47). CSC occurred in 61 patients (19.3%). Additional lymph nodes were retrieved in 47 of 61 patients (77.0%), with metastatic involvement in 10 of 47 patients (21.3%). Stage migration occurred in 3 of 316 patients (0.9%). ICG fluorescence showed a high false-positive rate for nodal metastases. Conclusion Although ICG frequently led to additional dissection of nodal stations after standard white-light D2 lymphadenectomy, it rarely resulted in stage migration. Use of ICG fluorescence to optimize lymph node dissection likely does not have a clinically relevant benefit in Western patients with gastric cancer.