Intraoperative indocyanine green lymphography during lymph node dissection in patients with colorectal cancer liver metastases

Purpose of the study . To evaluate the diagnostic performance of intraoperative fluorescence lymphography in patients with colorectal liver metastases (CLM). Patients and methods . The study included 55 patients with CLM who underwent intraoperative fluorescence lymphography with indocyanine green (ICG) during laparotomy to guide hepatic hilum lymph node dissection (LND) and liver resection. The first three fluorescent lymph nodes (LNs), defined as sentinel lymph nodes (SLNs), were identified within 30–45 minutes after peritumoral ICG injection. LND was performed with excision and labeling of SLNs and all fluorescent LNs detected during the observation period, as well as lymph nodes from stations 12, 13, and 8, regardless of fluorescence. Liver resection was subsequently performed. Results . In six of 55 patients (10.9 %), no SLNs were visualized. These patients underwent LND with removal of lymph nodes from stations 12, 8, and 13; histopathological examination revealed no LN metastases in this subgroup. In the remaining patients (89.1 %, n = 49), SLN fluorescence was observed. Histopathological analysis demonstrated lymphogenous metastases in 11 of 55 patients (20.0 %). In four of these 11 patients (36.3 %), selective LND based solely on preoperative imaging and intraoperative assessment would have failed to identify and remove metastatic LNs. The sensitivity of ICG lymphography was 100 %: in all 11 patients with nodal metastases, at least one SLN (SLN No1, No2, or No3) was involved. In two cases (18.2 %), metastatic involvement was detected only in SLN No3, with SLN No1 and SLN No2 being negative. Only one of the 11 patients (9.1 %) had additional metastatic LNs beyond the SLN basin; in this patient, all three SLNs were metastatic. Conclusion . Hepatic hilum LN metastases were detected in one in five patients with CLM. Reliable preoperative or intraoperative identification of metastatic hilar LNs remains challenging. ICG-guided SLN mapping enables more precise lymph node dissection. Further studies are required to determine whether this approach improves long-term oncological outcomes after liver resection for CLM.