A Prospective Cohort Study Comparing Colorimetric and Fluorescent Imaging for Sentinel Lymph Node Mapping in Endometrial Cancer.

Background: This prospective cohort study aimed to assess sentinel lymph node (SLN) mapping using isosulfan blue (ISB) compared with ISB plus indocyanine green (ICG) and near-infrared imaging (NIR) for patients with endometrial cancer.
Methods: In this study, 200 patients with endometrial cancer underwent SLN assessments and were randomized to ISB + ICG (n = 180) or ISB alone (n = 20). Blue dye determinations were recorded for all 200 cases followed by NIR imaging of ICG for 180 randomized subjects. All the patients underwent robotically assisted hysterectomy with pelvic ± aortic lymphadenectomy.
Results: The mean age of the patients was 64.5 ± 8.4 years, and the mean body mass index (BMI) was 33 ± 7.6 kg/m ² . The histologies were endometrioid G1 (43%), G2 (30%), G3 (7%), and type 2 (20%). The mean time from dye injection to initiation of mapping was 13.4 ± 6.2 min, and the time to removal of SLN was 17.4 ± 11.2 min. Detection of SLN for the 20 ISB control cases did not differ from that for the 180 ISB + ICG cases (p > 0.05). The rates of SLN detection for ISB + ICG/NIR (n = 180) versus ISB (n = 200) were as follows: bilateral (83.9 vs. 40%), unilateral (12.2 vs. 36%), and none (3.9 vs. 24%) (p < 0.001). The median SLN per case was 2 (range 0-4). Positive SLNs were found in 21.1% (n = 38) of the ISB + ICG cases compared with 13.5% (n = 27) of the ISB cases (p = 0.056). The false-negative rate for SLN biopsy was 2.5% (95% confidence interval, 0.1-14.7%). In 61% (25/41) of the node-positive cases, SLN was the only positive lymph node (LN). Isolated tumor cells were found in 39.5% (15/38) of the SLN metastasis cases compared with 26.7% (4/15) of the non-SLN metastasis cases (p = 0.528).
Conclusions: In this prospective study, ISB + ICG and NIR detected more SLNs and more LN metastases than ISB alone. Assessment of SLN with ICG + ISB/NIR imaging had excellent sensitivity for detection of metastasis and no safety issues.