Protocol for a phase II interventional trial investigating indocyanine green (ICG) fluorescence guided lymph node mapping for determination of bowel resection margins in colon cancer (ISCAPE).

Background: Optimal extent of lymph node dissection for colon cancer is debatable. Extensive lymphadenectomy may increase complication rate, while limited lymph node dissection may compromise oncological outcome. One of promising ways to find balance is to tailor extent of lymph node dissection to patient's individual anatomy using ICG lymphatic mapping. Methods: This is a single center interventional phase II trial with single group assignment aiming to determine if ICG lymphatic mapping sensitivity is sufficient to guide resection margins selection in colon cancer surgery. The trial's primary endpoint is proportion of pN+ patients in which affected lymph nodes are detected only within margins of ICG spread. Sample size of 101 patients was calculated using Buderer method Results: If after 101 ICG lymphatic mapping procedures, sensitivity of >96% is observed, this will provide rationale behind tailoring resection margins to fit ICG spread. Conclusions: ICG lymphangiography allows a surgeon to see locoregional lymphatics of a tumor site in real time and tailor colon and mesentery resection margins to meet oncological and functional needs. More data is needed to make this approach more widespread.