Indocyanine green (ICG)-guided lymphadenectomy during complete mesocolic excision of colorectal cancer: a narrative overview

Objective: To review and discuss the rationale, technique and results of indocyanine green (ICG)-guided lymphadenectomy Background: In recent years, more radical surgeries such as complete mesocolic excision with central vascular ligation and the Japanese D3 lymphadenectomy have been increasingly adopted as the optimal approach for colorectal cancer. These approaches share a specific focus on the extent of lymphadenectomy. While lymph node metastases are a major determinant of prognosis and a key factor for deciding further management, it has been recognized that the extent of lymphadenectomy, which in turns affect the number of lymph node harvested, might have a therapeutic effect with improved survival in patients with a higher number of dissected lymph nodes. However, individual variations of the lymphatic flow pattern, with possible extramesocolic diffusion, have been described for all colonic area, in particular for tumors of the hepatic and splenic flexures. In addition, the definition of the area to dissect, in particular the D3 area, is based on anatomical landmarks that might vary due to frequent vascular variants. Therefore, the possibility of directly visualize the regional nodal basin might increase the precision of an individualized lymphadenectomy. ICG is a fluorescent fluorophore that, after direct tissue injection, migrates in lymphatics and lymph nodes providing an intraoperative map of the tumor-specific draining area. Methods: A through literature search was done to identify pertinent articles. Conclusions: Although few studies exist, data indicate the potential of using this technique to guide the lymphadenectomy: complex surgical procedures seem facilitated and the extent of resection is tailored to include, in up to 34% of patients, lymph nodes that otherwise would not be harvested, resulting in a higher lymph nodes yield. real-time visualization of the lymphatic map during CME CVL may help to prevent iatrogenic rupture of the lymph vessels and/or lymph nodes with consequent tumor spillage