Abstract P4-07-12: An evaluation of lymphovascular invasion in relation to biology and prognosis according to subtypes in invasive breast cancer

Abstract

Abstract Background: Lymphovascular invasion (LVI) is associated with a poor outcome in breast cancer. The purpose of this study was to evaluate the clinical significance of LVI in primary breast cancer and to investigate disease-free survival (DFS) as a prognostic marker according to the breast cancer subtypes. The clinical significance of LVI was analyzed to investigate the biology and prognosis. Patients and Methods: This study examined 4,652 consecutive invasive breast cancer cases excluding the patients with non-invasive cancer, Stage IV and neo-adjuvant therapy from February 2002 to February 2021. Clinicopathological characteristics and prognosis of LVI positive and negative tumors were compared. LVI was evaluated in hematoxylin and eosin staining specimen from surgically resected samples. The ER, PgR, Ki-67, p53, HER2 status were evaluated using immunohistochemistry (IHC). Breast cancer subtypes were categorized based on the IHC data derived from ER/PgR, HER2 and Ki-67 (cutoff point: 20%) in invasive tumors. The median follow-up period was 95 months. Results: The LVI expression rates were 29.2%(low: 19.7% and high: 9.5%)in all primary cases. The LVI positive rate significantly correlated with ER/PgR negative, HER2 positive, p53 overexpression, higher Ki-67 index values, higher nuclear grade, positive nodes, and larger tumor. Moreover, the subtypes significantly correlated 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 DFS between LVI status in Luminal A, Luminal B, and TN subtypes, but there were 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. Conclusion: LVI significantly correlated with the advanced and aggressive characteristics in breast cancer. Luminal A type had a lower LVI rate and HER2 type had a higher rate. Moreover, LVI was a significant prognostic factor in Luminal B and TN subtypes. These data suggest that the LVI status was useful in predicting the prognosis in HER2 negative breast cancer. Citation Format: Reiki Nishimura, Tomofumi Osako, Yasuhiro Okumura, Masahiro Nakano, Hiroko Otsuka, Mamiko Fujisue, Nobuyuki Arima. An evaluation of lymphovascular invasion in relation to biology and prognosis according to subtypes in invasive breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-07-12.