Intraoperative Identification of Colonic Tumor Sites Using a Near-Infrared Fluorescence Endoscopic Imaging System and Indocyanine Green.

ABSTRACT

BACKGROUND: This study aimed to investigate the feasibility of the PINPOINT® Endoscopic Fluorescence Imaging System (PINPOINT) for intraoperative identification of colonic tumor sites during laparoscopic colorectal surgery. METHODS: Eighty consecutive patients with colorectal cancer were prospectively enrolled. Preoperatively, 0.5 mL of indocyanine green (ICG; 2.5 mg/mL) was injected into the submucosal space only at the distal side of the tumor under colonoscopy. Intraoperatively, we identified the tumor site on a PINPOINT image in which near-infrared fluorescence was superimposed in pseudocolor on a white light image. We estimated the intraoperative visibility rate of the tumor site and safety of ICG injection and assessed the interobserver variability of visibility grade between 2 surgeons. RESULTS: The intraoperative visibility rate of the tumor site was 93.8% (75/80). The visibility rate at an interval between injection and surgery of <7 days was significantly better than that at an interval of ≥10 days (p < 0.001). The kappa value between 2 observers was 0.827 (95% CI 0.635-1.019) with an agreement rate of 92.5%. There were no preoperative adverse reactions to ICG or intraoperative complications. CONCLUSIONS: Using ICG with the PINPOINT for identifying colonic tumor sites was feasible without any adverse effects during laparoscopic colorectal surgery.