Potential roles of lymphovascular space invasion based on tumor characteristics provide important prognostic information in T1 tumors with ER and HER2 positive breast cancer

Purpose Patients presenting with lymphovascular space invasion (LVSI) had an absolute decrease in survival. In our present study, the potential roles of LVSI on tumor characteristics was explored to predict the difference in the prognosis of ER and HER2 positive T1 tumors. Methods A total of 142 breast cancer patients diagnosed with ER+ and HER2+ tumors whose tumor size was ≤ 2 cm were included in this analysis. One hundred forty-two patients were divided into four groups, group 1 (lymph nodes+ and LVSI+), group 2 (lymph nodes+ and LVSI−), group 3 (lymph nodes− and LVSI+), group 4 (lymph nodes− and LVSI−). Univariate and multivariate Cox proportional hazard models were used to identify independent prognostic factors and calculate the HR and 95% CI. Kaplan–Meier and Cox regression models were used to test the prognostic significance. Results LVSI positivity was significantly associated with patient age, menopausal status, tumor size, lymph node status, Ki67, PR, and tumor grade. In the univariate and multivariate model, LVSI, PR, and Ki67 were significantly associated with DFS, and LVSI, lymph node status, PR, and Ki67 were significantly associated with OS. LVSI was significantly related to increased risk of DFS and OS only in the PR-negative and low-positive subgroups. It was a prognostic factor for DFS but not for OS in women with low Ki67 and was associated with DFS and OS in high-Ki67 tumors. Furthermore, patients who presented with only LVSI had a significantly worse survival rate than those with lymph node metastasis without LVSI in small tumors. Conclusion The presence of LVSI was highlighted as a variable significant to survival. In further clinical practice, patients with LVSI may need more intensive treatment in certain populations.