552P The prognostic evaluation of lymph-vascular space invasion to patients with endometrioid cancer and non-endometrioid cancer

Abstract

The impact of lymph-vascular space invasion (LVSI) on the prognosis of endometrial cancer (EC) patients remains controversial and lacks support from large sample size studies. Very few have examined whether LVSI is related to prognosis of non-endometrioid cancer patients. Our goal was to determine the impact of LVSI on the clinical prognosis of patients with endometrioid and non-endometrioid cancer respectively. This multicenter retrospective cohort study used the Chinese Endometrial Carcinoma Consortium database to identify 3715 women with endometrioid and non-endometrioid cancer who underwent initial surgical treatment between January 1, 2010 and December 31, 2019 and without other malignancies. The median (interquartile range) duration of follow-up was 39 (22-63) months. Patients were stratified based on histopathologic types and LVSI status. A propensity score matching (PSM) algorithm was used to balance the clinical characteristics (ratio 1:1). The impact of LVSI on the prognosis was examined using Kaplan-Meier analysis. univariate and multivariate Cox proportional hazards regression analyses were performed to identify independent high-risk factors of DFS and OS. The end points were disease-free survival (DFS) and overall survival (OS) and were assessed in the endometrioid and non-endometrioid cancer population. Among the 3715 women, LVSI was found in 346 (9.31%) cases. In the after PSM cohorts, LVSI significantly decreased the DFS (P=0.005), but not OS (P=0.66) of endometrioid cancer patients. For patients with non-endometrioid cancer, there was no statistical difference in DFS (P=0.54) or OS (P=0.51). In multivariate Cox proportional hazards regression, LVSI was an independent risk factor of DFS (hazard ratio [HR], 2.62 [95% CI, 1.35-5.10]; P=0.005) and not OS (HR, 1.24 [95% CI, 0.49-3.13]; P=0.66) for endometrioid cancer patients. LVSI was not a prognostic factor of neither DFS (HR, 1.28 [95% CI, 0.58-2.81]; P=0.54) or OS (HR, 1.33 [95% CI, 0.55-3.13]; P=0.52) for non-endometrioid cancer patients. The presence of LVSI was associated with decreased DFS of endometrioid cancer patients, and had no influence on the prognosis of non-endometrioid cancer patients.