Magnitude of risk for nodal metastasis associated with lymphvascular space invasion for endometrial cancer.

OBJECTIVES: While lymphvascular space invasion (LVSI) is a risk factor for nodal metastasis in endometrial cancer, the magnitude of risk is poorly described. We examined the risk of nodal metastasis associated with LVSI for various combinations of tumor grade and depth of invasion and examined the effect of LVSI on survival. METHODS: We identified patients with T1A (<50% myoinvasion) and T1B (>50% myoinvasion) endometrioid adenocarcinomas of the endometrium diagnosed between 2010 and 2012 and recorded in the National Cancer Database. The risk of nodal metastasis associated with LVSI stratified by grade and stage is reported. The association of LVSI and survival was examined using Kaplan-Meier analyses and Cox proportional hazards models. RESULTS: We identified 25,907 patients, including 3928 (15.2%) with LVSI. Among patients with LVSI, 21.0% had positive lymph nodes, compared to 2.1% in patients without LVSI (P<0.0001). In analyses stratified by stage and grade, LVSI was associated with increased risks of LN metastasis by a magnitude of 3 to over 10-fold. In a multivariable model controlling for clinical and demographic characteristics, the risk ratio of nodal disease with LVSI was 9.29 (95% CI, 7.29-11.84) for T1A tumors and 4.64 (95% CI 3.99-5.39) for T1B tumors. LVSI was associated with decreased survival even after adjustment for the presence of lymph node metastases (HR=1.92, 95% CI 1.56-2.36). CONCLUSIONS: LVSI is independently associated with lymph node metastases in women with apparent early-stage endometrial cancer and an independent predictor of survival even after adjustment for the presence of lymph node metastases.