Intraoperative use of fluorescence with indocyanine green reduces anastomotic leak rates in rectal cancer surgery: an individual participant data analysis

Background Fluorescence imaging by means of Indocyanine green (ICG) has been applied to intraoperatively determine the perfusion of the anastomosis. The purpose of this Individual Participant Database meta-analysis was to assess the effectiveness in decreasing the incidence of anastomotic leak (AL) after rectal cancer surgery. Methods We searched PubMed, Embase, Cochrane Library and ClinicalTrial.gov, EU Clinical Trials and ISRCTN registries on September 1st, 2019. We considered eligible those studies comparing the assessment of anastomotic perfusion during rectal cancer surgery by intraoperative use of ICG fluorescence compared with standard practice. We defined as primary outcome the incidence of AL at 30 days after surgery. The studies were assessed for quality by means of the ROBINS-I and the Cochrane risk tools. We calculated odds ratios (ORs) using the Individual patient data analysis, restricted to rectal lesions, according to original treatment allocation. Results The review of the literature and international registries produced 15 published studies and 5 ongoing trials, for 9 of which the authors accepted to share individual participant data. 314 patients from two randomized trials, 452 from three prospective series and 564 from 4 non-randomized studies were included. Fluorescence imaging significantly reduced the incidence of AL (OR 0.341; 95% CI 0.220-0.530;p < 0.001), independent of age, gender, BMI, tumour and anastomotic distance from the anal verge and neoadjuvant therapy. Also, overall morbidity and reintervention rate were positively influenced by the use of ICG. Conclusions The incidence of AL may be reduced when ICG fluorescence imaging is used to assess the perfusion of a colorectal anastomosis. Limitations relate to the consistent number of non-randomized studies included and their heterogeneity in defining and assessing AL. Ongoing large randomized studies will help to determine the exact role of routine ICG fluorescence imaging may decrease the incidence of AL in surgery for rectal cancer.