P1.191. A Novel ICG Fluorescence-Based Risk Stratification Tool for Post-Esophagectomy Anastomotic Leak (FLARE Score)

Abstract

Esophageal Cancer: Surgical Treatment of Esophageal Cancer Anastomotic leak remains the most feared complication after esophagectomy, with reported rates of 5–20%. Indocyanine green (ICG) fluorescence angiography enables real-time perfusion assessment, yet no validated scoring system integrates ICG parameters with clinical risk factors. We aimed to develop and internally validate the FLARE (Fluorescence-guided Anastomotic Leak Risk Evaluation) score. Ambispective analysis of 148 consecutive esophagectomy patients (January 2022–June 2025): prospective-ICG group (n=71) and retrospective non-ICG group (n=77). Primary outcome: anastomotic leak. Univariate analysis used Fisher's Exact Test/Chi-Square Test and Mann-Whitney U test. The 3-variable Clinical-EARS (Esophageal Anastomotic Leak Risk Score) was derived using OR-weighted integer assignment from statistically significant predictors: male sex (3 points), active smoking (2 points), tracheostomy (1 point); maximum 6 points. Variables with ROC-AUC below 0.60 (operative duration, blood loss) were excluded on statistical grounds. Internal validation was performed in the non-ICG cohort using bootstrap resampling (n=2000 iterations) with Hosmer-Lemeshow calibration testing and 5-fold cross-validation. The ICG-FLARE score additionally incorporated ICG perfusion peak time greater than 20 seconds (3 points) and ICG–naked eye assessment mismatch (3 points); maximum 12 points. Secondary outcomes included chyle leak. Anastomotic leak occurred in 7.0% (ICG) versus 15.6% (non-ICG; OR=0.41, p=0.171). ICG significantly reduced chyle leak (1.4% vs 11.7%; OR=0.11; p=0.018). Male sex (OR=10.53; p=0.006) and smoking (OR=4.74; p=0.018) were the only independent predictors on univariate analysis. Clinical-EARS stratified risk stepwise across all 148 patients: Low (0–1 pts) 2.4%, Medium (2–3 pts) 5.4%, High (4–6 pts) 20.3% (AUC=0.734; 95%CI: 0.640–0.821). Internal validation in the non-ICG cohort confirmed discrimination (AUC=0.685; 95%CI: 0.563–0.798) with minimal optimism (0.049) and excellent calibration (Hosmer-Lemeshow p=0.977). ICG-FLARE substantially improved performance in ICG patients (AUC=0.918; 95%CI: 0.802–0.998; ΔAUC=+0.159). At the optimal cutoff (≥7 points), ICG-FLARE achieved a sensitivity 80.0% and a specificity 90.9%. Perfusion peak time greater than 20 seconds (OR=14.86; p=0.013) and ICG–naked eye mismatch (OR=18.3; p=0.009) were independently predictive. The FLARE score provides validated, clinically actionable risk stratification for anastomotic leak after esophagectomy. Clinical-EARS achieves robust discrimination (AUC=0.734) with excellent calibration and internal validation, applicable to all patients regardless of ICG availability. ICG-FLARE dramatically enhances performance (AUC=0.918; sensitivity 80%, specificity 90.9%), demonstrating that ICG fluorescence angiography delivers independent prognostic information beyond clinical factors alone. Prospective external validation is warranted.