# Indocyanine Green Near-Infrared Fluorescence-Guided Sentinel Lymph Node Biopsy in Colon Cancer

## TL;DR

This study shows that using indocyanine green with near-infrared imaging helps identify sentinel lymph nodes in colon cancer patients during surgery.

## Contribution

The study demonstrates the feasibility and safety of ICG-guided NIR fluorescence for sentinel lymph node biopsy in colon cancer.

## Key findings

- SLNs were successfully identified in 83.33% of cases using ICG-guided NIR fluorescence.
- Atypical lymphatic drainage patterns were observed in 6.6% of patients and were linked to metastases later.
- Immunohistochemistry failed to detect micrometastases in SLNs initially deemed negative.

## Abstract

Background/Objectives: Indocyanine green (ICG)-guided near-infrared (NIR) fluorescence imaging represents a potentially advantageous approach for the identification of lymphatic drainage pathways. This study was undertaken to evaluate the efficacy of ICG-guided NIR fluorescence in mapping lymphatic drainage and facilitating sentinel lymph node biopsy (SLNB) in patients diagnosed with colon cancer. Methods: A prospective cohort of 30 consecutive patients with colon cancer undergoing surgical resection at our institution was enrolled in this study. Peritumoral injection of ICG was performed to facilitate intraoperative identification of sentinel lymph nodes (SLNs). Identified SLNs were marked and excised ex vivo following specimen retrieval. All the retrieved specimens were submitted for histopathological analysis using hematoxylin and eosin (H&E) staining. SLNs that were negative for metastatic disease upon H&E staining underwent further examination via immunohistochemistry (IHC). Results: Successful identification of SLNs was achieved in 83.33% of cases. The false positive rate was 6.6%, and the false negative rate was 8%, respectively. Atypical lymphatic drainage patterns were observed in 6.6% of the patients. Notably, the patients exhibiting atypical lymphatic drainage subsequently developed metastases during the follow-up period. Immunohistochemical analysis failed to detect micrometastases in SLNs that were initially deemed negative based on H&E staining. Conclusions: NIR–ICG fluorescence is a safe, reliable, and technically feasible method for performing SLNB in patients with colon cancer. Furthermore, this technique offers the potential for intraoperative identification of atypical lymphatic drainage pathways, which may have significant implications for determining the optimal extent of standard lymphadenectomy.