Introduction/Background*Our objective was to describe the incidence of lymph node metastasis in patients with surgically staged endometrioid-type endometrial cancer in Donostia Hospital and evaluate the presence of isolated aortic metastasis. We believe, based on recent literature and our experience, that the number of lymph nodes involved in the aortic area is higher than traditionally reported.

Methodology A prospective observational study was conducted between 13 June 2014 and 31 December 2020 with 333 patients that underwent laparoscopic surgery for endometrial cancer at our institution. In all low, intermediate, high-intermediate and high ESGO/ESTRO/ESP 2020 prognostic risk cases, we performed sentinel lymph node (SLN) biopsy with dual cervical and fundal indocyanine green injection. All SLNs were processed with an ultrastaging technique. A total of 152 patients also underwent total pelvic and paraaortic lymphadenectomy.

Result(s)*The detection rates were as follows: 94% overall for SLNs; 91.3% overall for pelvic SLNs; 70.5% for bilateral SLNs; 67.2% for paraaortic SLNs, 53.6% in 3 areas. A median of one aortic node and two pelvic nodes were removed. We detected positive SLNs in 56 patients (16.8% of total cases); both pelvic and aortic SLNs were positive in 10 cases (representing 3% of the sample; 17.8% of the total number of patients with positive nodes), while only pelvic SLNs were positive in 32 (9.6%; 57.1%) and only aortic SLNs were positive in 14 (4.2%; 25%). Sorting by myometrial infiltration, <50% and >=50%, aortic isolated SLNs were positive in 4 and 10, representing 7.1% and 17.8% of the total with positive nodes (Fischer-Test Statistically significant), respectively.

Conclusion*In our series, the incidence of isolated aortic nodal metastasis is high compared with published reports. SLN biopsy allows a high rate of aortic detection, identifying a non-negligible percentage of isolated aortic metastases. Aortic metastases in endometrial cancer are possible and we should not give up actively looking for them. The highest rate of isolated aortic metastases occurred in patients with high-risk tumors, although there were also cases in patients with low-risk tumors.