A narrative review of intraoperative use of indocyanine green fluorescence imaging in gastrointestinal cancer: situation and future directions

Background and objective: As a surgical tool, indocyanine green (ICG) is increasingly used in surgery, especially in gastric and colorectal surgery. The use of ICG fluorescence imaging can improve the accuracy of tumor resection and potentially improve surgical outcomes for cancer patients. However, there are still different opinions or controversies on the application of ICG in the literature and the administration of ICG is still not uniform. In this review, we summarize the current status of its application and ICG administration methods in gastrointestinal cancer and discuss its existing limitations and future research directions.

Methods: Literature published in the PubMed database from 1969 to 2022 was searched for using the keywords "Indocyanine green or near-infrared imaging or ICG", "gastric cancer", "gastroesophageal junction cancer", and "colorectal cancer" to summarize the main applications of ICG in gastrointestinal cancers.

Key content and findings: ICG guidance can rapidly determine tumor location and save operative time, and can also visualize lymph nodes (LNs) in real-time, helping surgeons to retrieve more LNs for better postoperative staging, but its use in identifying sentinel lymph node (SLN) in gastric cancer (GC) remains controversial due to false negatives. ICG fluorescent angiography has great potential in preventing colorectal anastomotic leakage, but there is a dearth of high-caliber research evidence. In addition, ICG has unique advantages in detecting colorectal liver micrometastasis. Notably, there is still no uniform administration method and dose of ICG.

Conclusions: In this review, we summarize the current status of ICG application in gastrointestinal cancer, and the current literature suggests that it is safe and effective and has the potential to change the clinical outcome of patients. Therefore, ICG should be routinely used in gastrointestinal cancers to improve the surgical outcomes of patients. In addition, this review summarizes the ICG administration in the literature, and we expect future guidelines to unitize and standardize the administration of ICG.