Postoperative Complications After Indocyanine Green-Guided Colorectal Cancer Surgery: Report of an Unexpected...

Indocyanine green fluorescence angiography (ICG-FA) is increasingly used in colorectal cancer surgery to assess intraoperative anastomotic perfusion and potentially reduce postoperative complications, particularly anastomotic leakage. However, the magnitude and consistency of the benefit remain debated, especially regarding complication severity. We report the impact of ICG-FA on postoperative complications in a single-center prospective comparative cohort study with cluster-based group allocation, with particular focus on an unexpected severity signal observed in our data.

Between January 2020 and December 2025, 315 patients undergoing elective resection for colorectal cancer were prospectively enrolled at a tertiary surgical department in Bucharest, Romania. Group allocation was determined by the temporal availability of the operating theater equipped with a near-infrared laparoscopic tower (one to two days per week, dedicated to extensive laparoscopic procedures). Sixty-six patients underwent ICG-FA-guided resection (3 mg intravenous bolus, standard institutional protocol); 247 underwent conventional resection. Primary outcomes were overall postoperative complications (Clavien-Dindo grade II or higher) and severe complications (anastomotic leak or Clavien-Dindo grade III or higher). Statistical analyses were performed with JASP version 0.94.5.

The overall complication rate was 31.8% in the ICG group versus 39.4% in the non-ICG group, a numerical reduction that did not reach statistical significance (chi-square = 1.26, p = 0.26). The postoperative hospital stay was significantly shorter in the ICG group (6.92 ± 4.78 days vs. 9.21 ± 8.07 days, p < 0.01). Among patients who developed any postoperative complication (n = 119), the proportion of severe complications was significantly higher in the ICG arm: 28.57% (6/21) versus 9.18% (9/98) in the non-ICG arm (chi-square = 5.90, p = 0.02; Fisher log odds ratio = 1.38, p = 0.03). Multivariate logistic regression identified right-colon tumor location as the strongest independent predictor of postoperative complications (odds ratio = 7.01, p < 0.01), with preoperative albumin showing a borderline protective effect (odds ratio = 1.94, p = 0.05).

In our cohort, ICG-FA was associated with shorter hospital stay and a non-significant reduction in overall complications, but with an unexpected and statistically significant increase in the proportion of severe complications among patients who developed any complication. We discuss this counter-intuitive finding openly, considering three plausible mechanisms: statistical fragility related to small event numbers, confounding by procedural complexity inherent to the cluster-based design, and a real component possibly related to false reassurance and learning curve effects. Honest reporting of such signals is essential for refining the appropriate clinical use of ICG-FA. Larger, stratified, prospective studies are needed to clarify whether the observed signal reflects a true phenomenon or chance.