Indocyanine green (ICG) fluorescence guided lymph node mapping for determination of resection margins in colon cancer - ISCAPE trial.

BACKGROUND: Indocyanine green (ICG) lymphangiography for colon cancer has been regarded as a sentinel lymph node (LN) detection tool, but its repeatedly reported suboptimal sensitivity rates suggest that approach aiming to define locoregional lymphatic collector margins might be more efficient in guiding surgeon's decision making. Thus, present study was designed to determine if sensitivity of the latter approach is sufficient to guide resection margins' selection in colon cancer surgery. METHODS: This is a prospective, single-centre, single-arm phase II interventional trial, including patients with histologically confirmed colon adenocarcinoma. ICG was injected subserosally in the beginning of operation, fluorescence was assessed 30 min after injection or later, when it became detectable. Primary endpoint was proportion of pN + patients in whom all metastatic lymph nodes were located within the area of fluorescence of lymphatics (AFL). Secondary endpoints included feasibility, safety, lymphatic spread patterns and proportion of resections modified based on ICG mapping. RESULTS: Between 26 July 2022 and 27 February 2024, 101 patients underwent colectomies with intraoperative ICG lymphatic mapping. AFL was registered in all cases. Average lateral spread was 5.87 ± 3.20 proximally and 5.89 ± 2.54 cm distally. In two of 46 pN + cases affected LNs were discovered beyond AFL. ICG lymphatic mapping sensitivity was found to be 95.6%, which was beyond 0.960-0.990 interval, so null hypothesis was retained. CONCLUSIONS: In this trial, metastatic LNs were confined within ICG AFL in 95.6% of pN + cases. Although the predefined sensitivity threshold was not met, the result suggests potential for ICG mapping to guide resection margins in colon cancer surgery.