The prognostic and clinical significance of substantial lymphovascular space invasion in early-stage endometrial carcinoma
Substantial lymphovascular space invasion (LVSI) has been incorporated into the 2023 International Federation of Gynecology and Obstetrics (FIGO) staging system for endometrial carcinoma. This study aims to evaluate whether classifying LVSI into substantial LVSI (≥5 involved vessels) and no/focal LVSI (≤4 involved vessels) provides meaningful prognostic differentiation in early-stage endometrial carcinoma. We retrospectively enrolled patients with FIGO 2009 stage I-II endometrial carcinoma who underwent surgical staging between January 2013 and August 2020. LVSI was graded as no LVSI, focal LVSI (1-4 involved vessels), or substantial LVSI (≥5 involved vessels), following the World Health Organization 2020 definition. Among 1796 patients, 112 (6.2 %) had substantial LVSI, 170 (9.5 %) had focal LVSI, and 1514 (84.3 %) had no LVSI. The 5-year progression-free survival (PFS) rates were 81.7 % for substantial LVSI, 89.9 % for focal LVSI, and 95.0 % for no LVSI (P < 0.001). Multivariate analysis found that substantial LVSI was an independent predictor of worse PFS (substantial vs. no LVSI: HR 2.49, P < 0.001; substantial vs. focal LVSI: HR 1.90, P = 0.047). No statistically significant difference in PFS was observed between patients with focal LVSI and those with no LVSI (HR 1.31, P = 0.321). The overall survival (OS) analysis showed consistent results. Substantial LVSI is an independent prognostic factor for PFS and OS in early-stage endometrial carcinoma, while focal LVSI shows similar outcomes to no LVSI. Our findings support the use of substantial LVSI (≥5 involved vessels) as a key determinant for risk stratification and staging, aligning with the FIGO 2023 staging system recommendations.