Diagnostic performance of fluorescent lymphography-guided lymph node dissection during minimally invasive gastrectomy following chemotherapy.

Background: Fluorescent lymphography-guided lymph node dissection (FL) using indocyanine green (ICG) during radical gastrectomy for gastric cancer has shown enhanced lymph node (LN) retrieval and high sensitivity in detecting LN metastases. However, the impact of FL during gastrectomy following chemotherapy remains uncertain because changes in the ICG injection site due to tumor shrinkage may potentially visualize different lymphatic drainage from the tumor. This study aimed to assess the diagnostic performance of FL during gastrectomy after preoperative chemotherapy.

Methods: This retrospective study included patients who underwent minimally invasive gastrectomy with FL following chemotherapy between January 2013 and February 2024. Patients were categorized according to their tumor response after chemotherapy based on endoscopic, radiologic, and pathological findings.

Results: Of 29 patients, 9.4 (range 8-12) LN stations containing 6.9 (range 3-11) fluorescent LN stations, which had 56.3 (range 33-99) LNs including 33.4 (range 11-68) fluorescent LNs, were retrieved per patient. While 52 metastatic LN stations were fluorescent, three non-fluorescent metastatic LN stations were identified in one patient (3.4 %). FL showed 94.5 % (52/55) sensitivity and 95.9 % (70/73) negative predictive value for detecting metastatic LN stations. There was no significant difference in the number of retrieved LNs and the sensitivity for detecting metastatic LN stations between responders and non-responders.

Conclusions: Tumor response after chemotherapy did not influence the diagnostic performance of FL. The diagnostic performance of FL during gastrectomy following chemotherapy was acceptable. Similar to upfront surgery, FL can be safely applied even after chemotherapy.