An evaluation of lymphovascular invasion in relation to biology and prognosis according to subtypes in invasive breast cancer.

Lymphovascular invasion (LVI) is associated with a poor outcome in breast cancer. The purpose of the present study was to evaluate the clinical significance of LVI in primary breast cancer and to investigate disease-free survival as a prognostic marker according to the breast cancer subtypes. This study examined 4,652 consecutive cases of invasive breast cancer excluding the patients with non-invasive cancer, stage IV and those who underwent neo-adjuvant therapy from February 2002 to February 2021. The clinicopathological characteristics and prognosis of LVI-positive and -negative tumors were compared. LVI was evaluated in H&E staining specimens from surgically resected samples. The LVI expression rates were 29.2% (low, 19.7%; high, 9.5%) in all primary cases. The LVI-positive rate was significantly associated with specimens with the following characteristics: ER/PgR-negative, HER2-positive, p53 overexpression, higher Ki-67 index values, higher nuclear grade, positive nodes and larger tumors. Moreover, the subtypes were significantly associated with LVI positivity; 20% in Luminal A, 34.6% in Luminal B, 40.9% in Lumina/HER2, 38.1% in HER2-enriched and 29.8% in triple negative (TN). There were significant differences in disease-free survival between LVI status in Luminal A, Luminal B and TN subtypes, but there was no difference in the Luminal/HER2 and HER2-enriched subtypes. A multivariate analysis revealed that LVI was a significant factor in Luminal B and TN subtypes. Overall, LVI was significantly associated with the advanced and aggressive characteristics in breast cancer. Luminal A type had a lower LVI rate, and HER2 type had a higher LVI rate. Moreover, LVI was a significant prognostic factor in Luminal B and TN subtypes. These data suggested that the LVI status was useful in predicting the prognosis in HER2 negative breast cancer cases.