In Vivo Sentinel Lymph Node Detection with Indocyanine Green in Colorectal Cancer

Introduction: The indocyanine green fluorescence imaging system allows the identification of lymphatic vessels, lymph nodes and blood flow during surgery. Colorectal cancer is the second commonest cancer in women, the third in men, being the fourth commonest cause of cancer death. One of the most important factors for staging and prognosis in colorectal cancer is the involvement of the regional lymph nodes. In the literature, there are several methods for identifying sentinel lymph nodes, including methylene blue, technetium (99m Tc) and indocyanine green. The current article presents the use of indocyanate in the identification of sentinel node/nodes in malignant tumors of the colon, by a technique performed in vivo, before the primary ligation of the vascular pedicles. Material and methods:The study was prospectively conducted on a group of 23 patients who had undergone a standard surgical resection - 21 of them for a malignant tumor of the colon and two patients for a malignant rectal tumor - in the 1st General Surgery Department, Emergency University Hospital, Bucharest, Romania, between January 2020-March 2022. During surgery, sentinel lymph node detection was performed using indocyanine green and the Karl Storz® Vitom ICG probe. Sentinel lymph nodes were separately excised and sent to the Department of Pathological Anatomy for analysis. Results:Sentinel nodes were successfully identified in 13 patients and the overall identification rate was 56.52% (13/23 cases). In seven cases, the number of invaded nodes was the same as that of identified and invaded sentinel nodes. Complete lymphadenectomy was performed in all cases regardless of the staining status of the sentinel lymph nodes. Conclusions:The use of fluorescence imaging with indocyanine green in colorectal cancer remains controversial. Since no specific receptor target is used, the fluorescent signal is not specific for lymph node metastases. The learning curve is particularly important for increasing the accuracy of the technique and is responsible for the negative results in some cases. Cases in which lymph nodes have not been invaded require further evaluation through immunohistochemistry and chain polymerization reaction (RT-PCR).