Comparative Analysis of Indocyanine Green and Methylene Blue for Sentinel Lymph Node Mapping in V-NOTES Staging Surgery for Endometrial Cancer

Objective This study aimed to assess the comparative effectiveness of indocyanine green (ICG) and methylene blue in the marking and identification of sentinel lymph nodes (SLN) during SLN biopsy procedures in patients diagnosed with endometrial cancer undergoing staging surgery through vaginal natural orifice transluminal endoscopic surgery (V-NOTES). Methods Consecutive patients with endometrial cancer who underwent staging surgery with V-NOTES at a single center between January 2024 and December 2025 were prospectively included in the study. Patients were randomly divided 1:1 into ICG and methylene blue groups. In the ICG group, ICG (2.5 mg) dissolved in 5 Ml of sterile water was injected subserosally into the cervix. In the methylene blue group, 5 mL of 1% methylene blue solution was injected into the cervix in the same way.The SLN identification rate, number of SLNs identified, bilateral SLN identification rate, surgical time, blood loss, complication rates and histopathologic results were recorded. Findings Eighty (ICG group, n = 40- methylene blue group, n = 40) were included in the study. The SLN identification rate was significantly higher in the ICG group (95%) than in the methylene blue group (82.5%) (p = 0.045). The mean number of SLNs identified in the ICG group (3.2 ± 1.1) was significantly higher than that in the methylene blue group (2.5 ± 0.9) (p = 0.021). The rate of bilateral SLN identification was higher in the ICG group (80%) than in the methylene blue group (65%), but the difference was not statistically significant (p = 0.112). Surgical time, blood loss and complication rates were similar between the two groups. Histopathological examination revealed a similar number of positive SLNs in both groups. Conclusion In the context of sentinel lymph node (SLN) biopsy for staging surgery utilizing V-NOTES in endometrial cancer, indocyanine green (ICG) has demonstrated a superior SLN identification rate and a higher yield of SLNs compared to methylene blue. Given the advantage of real-time imaging, ICG emerges as a promising agent for SLN biopsy in minimally invasive approaches such as V-NOTES.