Aortic sentinel node detection in endometrial cancer: 6 year prospective study

Abstract

Objective: The aim of this study was to describe our final results using dual cervical and fundal indocyanine green injection for the detection of sentinel lymph nodes (SLNs) in endometrial cancer along parametrial and infundibular drainage pathways.

Methods: We conducted a prospective observational study between 26 June 2014 and 31 December 2020 enrolling 332 patients that underwent laparoscopic surgery for endometrial cancer at our hospital. In all cases, we performed SLN biopsy with dual cervical and fundal indocyanine green injection identifying pelvic and aortic SLNs. All SLNs were processed with an ultrastaging technique. A total of 172 patients also underwent total pelvic and para-aortic lymphadenectomy.

Results: The detection rates were as follows: 94.0% overall for SLNs; 91.3% overall for pelvic SLNs; 70.5% for bilateral SLNs; 68.1% for para-aortic SLNs, and 3.0% for isolated paraaortic SLNs. We found lymph node involvement in 56 (16.9%) cases, macrometastasis in 22, micrometastasis in 12 and isolated tumor cells in 22. Fourteen patients had isolated aortic nodal involvement, representing 25% of the positive cases. There was one false negative (SLN biopsy negative but lymphadenectomy positive). Applying the SLN algorithm, the sensitivity of the dual injection technique for SLN detection was 98.3% (95% CI 91-99.7), specificity 100% (95% CI 98.5-100), negative predictive value 99.6% (95% CI 97.8-99.9), and positive predictive value 100% (95% CI 93.8-100). Overall survival at 60 months was 91.35%, with no differences between patients with negative nodes, isolated tumor cells and treated nodal micrometastasis.

Conclusions: Dual sentinel node injection is a feasible technique that achieves adequate detection rates. Additionally, this technique allows a high rate of aortic detection, identifying a non-negligible percentage of isolated aortic metastases. Aortic metastases in endometrial cancer account for as many as a quarter of the positive cases and should be considered, especially in high-risk patients.

Keywords: Endometrial cancer; Indocyanine green; Lymphadenectomy; Sentinel node.