EPV119/#397 Volume of Nodal Disease and Oncologic Outcomes in Endometrial Cancer Patients with Positive Sentinel Lymph Nodes: an Italian Multi-Institutional Study

Objectives To asses predictive factors for sentinel-lymph-nodes (SLNs) involvement and recurrence-free-survival (RFS) in patients with endometrial cancer Methods A multicenter retrospective evaluation of endometrial-cancer patients with positive (macro-micro metastases or ITCs) SLNs, treated between 2003 and 2020, was performed. Predictive factors for nodal involvement (endometrioid vs non-endometrioid histology, grading, lymphovascular-space-invasion (LVSI), myometrial-invasion (MI), cervical-stromal-invasion, ESGO/ESTRO/ESP risk group), adjuvant therapy and oncological outcomes were evaluated Results 142 patients were identified among 12 participating centers. In 64.8% of cases a low-volume disease (≤2 mm) was found in SLNs: 33 (23.2%) ITCs and 59 (41.6%) micrometastases. Predictors of macrometastatic SLNs were: high grade [p:0.002], LVSI [p:0.007] and MI >50% [p:0.008]. 17 (18.5%) patients with low-volume disease (8 micrometastases and 9 ITCs) did not receive any adjuvant therapy. At a mean follow-up of 34.6 months (range 1–215) months, 21 (14.8%) relapses were recorded, only one among patients not receiving any adjuvant.The RFS at 2-years for the micrometastatic patients was 91%, similar to ITCs patients (79.1%), regardless of adjuvant treatment, but statistically better than patients with macrometastases (72.3%) [p: 0.026].The only factors affecting RFS were deep MI [p:0.03] and cervical stromal invasion [p:0.046]. Conclusions More than half of patients with positive SLNs had low-volume disease. Grading, MI and LVSI predicted volume of nodal metastases. MI and cervical invasion affected RFS; while adjuvant treatment did not seem significantly associated with RFS in patients with low-volume disease. Longer follow-up time and a larger sample size are needed to understand the role of adjuvant therapy in low-volume metastatic SLNs.