Lymphovascular space invasion is an independent risk factor for nodal disease and poor outcomes in endometrioid endometrial cancer.

Objective: Adjuvant radiotherapy improves local control but not survival in women with endometrial cancer. This benefit was shown in staged patients with "high intermediate risk" (HIR) disease. Other studies have challenged the need for systematic staging including lymphadenectomy. We sought to determine whether LVSI alone or in combination with other histologic factors predicts lymph node (LN) metastasis in patients with endometrioid endometrial cancer.

Methods: A retrospective review was conducted of patients with endometrioid endometrial carcinoma who had confirmed presence/absence of LVSI and clinicopathologic data necessary to identify HIR criteria. Kaplan-Meier curves were generated and univariate and multivariate analyses performed as appropriate.

Results: We identified 757 eligible patients and 628 underwent systematic lymphadenectomy for staging purposes. In the surgically staged group, 242 (38%) patients met uterine HIR criteria and 196 (31%) had LVSI. Both HIR and LVSI were significantly associated with LN metastasis. Among the HIR positive group, 59 had LN metastasis (OR 4.46, 95% CI 2.72-7.32, P<0.0001). Sixty-six LVSI positive patients had nodal metastasis (OR 11.04, 95% CI 6.39-19.07, P<0.0001). The NPV of LVSI and HIR negative specimens was 95.6% and 93.4% respectively. In multivariate analysis, PFS and OS were significantly reduced in both LVSI positive (P<0.0001) and HIR patients (P<0.0001) when compared to patients who were LVSI and HIR negative.

Conclusions: HIR status and LVSI are highly associated with LN metastasis. These features are useful in assessing risk of metastatic disease and may serve as a surrogate for prediction of extrauterine disease.