Carbon dye versus indocyanine green for sentinel lymph node mapping in endometrial cancer: a prospective dual-center study.

Objective: To compare the detection rates and diagnostic accuracy of sentinel lymph node (SLN) mapping using carbon dye and indocyanine green (ICG) in patients with early-stage endometrial cancer.

Methods: The present study was a dual-center, prospective cohort study conducted between September 2021 and August 2022 involving patients with early-stage endometrial cancer. For SLN mapping, one center exclusively used carbon dye, while the other solely used ICG. Subsequently, all patients underwent complete systematic pelvic lymphadenectomy. The detection rates, sensitivity, and negative predictive value of SLN mapping were analyzed.

Results: This study included 179 patients, of whom 89 (49.7%) were mapped using carbon dye and 90 (50.3%) were mapped using ICG laparoscopically. Unilateral detection rates of SLNs were similar, 94.4% (84/89) for carbon dye and 97.8% (88/90) for ICG (p = .25). In contrast, bilateral detection rates were significantly higher with carbon dye compared to ICG (82.0% [73/89] vs 64.4% [58/90], p = 0.008). The sensitivity and negative predictive value were both 100% for ICG and 83.3% and 98.8% for carbon dye, respectively. The empty node packet rate was 5.6% (5/90) for ICG and 0% (0/89) for carbon dye (p = .17). Although this difference did not reach statistical significance, all cases of empty node packets were observed in patients with successful unilateral but failed bilateral detection.

Conclusions: Carbon dye is a safe and effective agent for SLN mapping, demonstrating adequate detection rates, satisfactory sensitivity, and a high negative predictive value in patients with early-stage endometrial cancer. The use of carbon dye might reduce the rate of empty node packets, thereby enhancing the accuracy of nodal evaluation. While carbon dye may be a promising alternative tracer, particularly in low-resource settings, further comparative studies are needed to evaluate its cost-effectiveness relative to other widely used tracers, including blue dyes.