Fluorescence-Guided Surgery in the Combined Treatment of Peritoneal Carcinomatosis from Colorectal Cancer: Preliminary Results and Considerations

Indocyanine green (ICG) is a near-infrared fluorescent contrast agent, which preferentially accumulates in cancer tissue. The aim of our study was to investigate the role of fluorescence imaging (FI) with ICG (ICG-FI) for detecting peritoneal carcinomatosis (PC) from colorectal cancer (CRC).Four CRC patients with PC scheduled for cytoreductive surgery + hyperthermic intraperitoneal chemotherapy were enrolled in this prospective study. At a median time of 50 min after 0.25 mg/kg ICG injected intravenously, intraoperative ICG-FI using Fluobeam(A (R)) was performed in vivo and ex vivo on all specimens. The Peritoneal Cancer Index was used to estimate the likelihood of complete cytoreduction.No severe complications were recorded. ICG-FI took a median of 20 min (range 10-30, IQR 15-25). Sixty-nine nodules were harvested. Fifty-two nodules had been diagnosed preoperatively by conventional imaging (n = 30; 43%) or intraoperatively by visual inspection/palpation (n = 22; 32%). With ICG-FI, 47 (90%) nodules were hyperfluorescent, and five hypofluorescent. Intraoperative ICG-FI identified 17 additional hyperfluorescent nodules. On histopathology, 16 were metastatic nodules. Sensitivity increased from 76.9%, with the conventional diagnostic procedures, to 96.9% with ICG-FI. The positive predictive value of ICG-FI was 98.4%, and test accuracy was 95.6%. Diagnostic performance of ICG-FI was significantly better than preoperative (p = 0.027) and intraoperative conventional procedures (p = 0.042). The median PCI score increased from 7 to 10 after ICG-FI (p < 0.001).Our results suggest that intraoperative ICG-FI can improve outcomes in patients undergoing CS for PC from CRC. Further studies are needed to determine the role of ICG-FI in this patient population.