Fluorescence-guided minimally-invasive surgery for colorectal liver metastases, a systematic review

Approximately 25-30% of patients with colorectal cancer (CRC) develop liver metastases (CRLM) over the course of the disease. To achieve curation surgical treatment of liver metastases is still considered as the gold standard. A shift from open to laparoscopic and robot-assisted surgery has occurred over the past decades. Extensive research has been performed using both preoperative as well as intraoperative imaging techniques to improve treatment planning, intraoperative tumor detection and evaluation of resection margins. Recently, increasing interest in near-infrared fluorescence (NIRF) imaging emerged as an intraoperative imaging modality in liver surgery. NIRF-guided liver surgery with the fluorescent dye indocyanine green (ICG) has been implemented as standard-of-care in various centers across the globe to aid in lesion differentiation and guidance of surgical margins. However, the low specificity and high false-positive rates of ICG in intraoperatively found lesions have led to the demand and development of tumor-specific fluorescent probes and improved camera systems. Here, we present a systematic review of available literature on intraoperative fluorescence imaging for minimally invasive CRLM surgery. Furthermore, we emphasize on fluorescent enhancement patterns, recent developments and future perspectives concerning fluorescent dyes and imaging techniques to optimize clinical application.