Intraoperative Use of Indocyanine Green Fluorescence in Hepatobiliary and Pancreatic Cancer Resections: Current State and Considerations

Abstract

Introduction: Surgery for hepatobiliary and pancreatic malignancies often has unfavourable outcomes due to incomplete resection, with positive histopathological margins and locoregional metastases. Intraoperative use of indocyanine green fluorescence (ICG) with near-red infrared light can improve tumor detectability and achieve R0 status. Methods: Review of current literature. Results: ICG fluorescence and bile excretion allows for real-time visualisation of malignant tissues and assessment of resection margins. In liver surgery it can identify subcapsular lesions, a property especially useful in minimally invasive surgery where there is loss of tactile feedback and direct visual inspection. It can also delineate hepatic segmental anatomy for anatomical resections. Hepatocellular carcinomas tend to uniformly uptake ICG, whereas primary or metastatic adenocarcinomas like cholangiocarcinomas and colorectal liver metastases as well as poorly differentiated hepatocellular carcinomas show rim enhancement. In pancreatic cancer, fluorescence of the resection margin has been shown to correspond to presence of malignancy on histopathological assessement. ICG can also help to detect micrometastases and extrahepatic spread and distinguish between scar tissue and disease following neoadjuvant chemoradiotherapy. However the technique has limitations: wide variability of method and dose of administration, no visualisation of deep seated lesions, high background fluorescence, false positives up to 40% requiring additional verification by other modalities like intraoperative ultrasound or frozen section for newly detected lesions. Conclusion: ICG fluorescence can offer increased detectability of malignancy and improve post-operative outcomes in hepatobiliary and pancreatic resections. However there are limitations such as superficial depth of detection and low specificity which need improvement to achieve maximum benefit.