Low-Volume Nodal Metastasis in Endometrial Cancer: Risk Factors and Prognostic Significance.

Objective: To evaluate the oncological outcomes of patients with low-volume metastasis compared to those with macrometastasis and negative nodes in endometrial cancer. Methods: A single institutional retrospective study was carried out, which included all patients with endometrial cancer who underwent surgical treatment between January 2007 and December 2016. We analyzed the progression-free survival (PFS) and overall survival (OS) of all patients after sentinel node biopsy and full nodal surgical staging according to their final pathological nodal status, focusing on the impact of the size of nodal metastasis. Results: A total of 270 patients were operated on during the study period; among them, 230 (85.2%) patients underwent nodal staging. On final pathology, 196 (85.2%) patients had negative lymph nodes; low-volume metastasis (LVM) was present in 14 (6.1%) patients: 6 (2.6%) patients had isolated tumor cells (ITCs) and 8 (3.5%) patients presented just micrometastasis; additionally, 20 (8.7%) patients presented macrometastasis. After a median (range) follow-up of 60 (0-146) months, patients with macrometastasis showed a significantly worse PFS compared to LVM and node-negative patients (61.1% vs. 71.4% vs. 83.2%, respectively; p = 0.018), and similar results were obtained for 5-year OS (50% vs. 78.6% vs. 81.5%, respectively; p < 0.001). Half of the patients presenting LVM did not receive adjuvant treatment. Moreover, LVM had a moderate nonsignificant decrease in 5-year PFS compared to node-negative patients. Conclusions: Patients with endometrial cancer and low-volume nodal metastasis demonstrated a better prognosis than those presenting macrometastasis. Low-volume metastasis did not show worse oncological outcomes than node-negative patients, although there was a slight decrease in progression-free survival.