Impact of tumor response to neoadjuvant chemotherapy on ICG-guided lymphadenectomy quality and surgical outcomes in gastric cancer.

INTRODUCTION

Indocyanine green (ICG)-guided lymphadenectomy has been shown to be a promising tool in enhancing nodal retrieval during gastric cancer (GC) surgery. However, its efficacy in patients treated with neoadjuvant chemotherapy (NAC) remains unclear. This study evaluates the impact of tumor response to NAC, based on Mandard classification, on lymphadenectomy quality and surgical outcomes in patients undergoing minimally invasive gastrectomy with ICG guidance.

MATERIALS AND

METHODS

We conducted a retrospective observational study including 34 patients, from a Western tertiary center, with locally advanced GC who underwent NAC followed by ICG-guided minimally invasive gastrectomy. Patients were stratified into two groups: responders (TRG 1-2) and non-responders (TRG 3-5). The primary outcome was the total number of retrieved lymph nodes. Secondary outcomes included surgical outcomes and postoperative complications.

RESULTS

ICG-guided lymphadenectomy was safe in both groups, with no significant differences in surgical complications, reoperation, mortality, or hospital stay. However, non-responders had a significantly higher lymph node yield (36.29 ± 20.90 vs. 24.65 ± 7.93; p = 0.011). This trend remained across surgical types and histological subtypes. All duodenal stump leaks occurred in responders, suggesting greater fibrotic changes post-NAC.

CONCLUSION

The application of ICG for lymphatic mapping in gastric cancer is both safe and feasible in patients receiving NAC. Poor tumor response is associated with higher lymph node retrieval, potentially due to preserved lymphatic architecture and better tracer diffusion. This finding supports the hypothesis that lymphatic fibrosis induced by treatment impairs tracer diffusion.