Prognostic role of lymphovascular invasion and lymph node status among breast cancer subtypes

Abstract

Context: Breast cancer subtype (BCS) and lymphovascular invasion (LVI) have both been independently demonstrated as prognostic factors.Aims: The objective of this investigation was to evaluate the prognostic power of LVI among BCSs.Settings and Design: From an institutional database, 2017 women with a histopathologically confirmed the diagnosis of breast cancer treated between January 2006 and December 2014 were consecutively selected.Subjects and Methods: Information recorded for each patient included age at diagnosis, year of diagnosis, and date of death or last contact. Total incidences of recurrence or death from breast cancer were ascertained from follow-up lasting until 31 June 2013. Institutional review board approval was obtained through our institution's human investigations committee.Statistical Analysis Used: Univariate and multivariate survival analysis were performed using the Kaplan–Meier analysis and Cox proportional hazards model with a stepwise backward elimination to derive a final model of variables with a significant independent relationship with overall survival (OS) and recurrent-free survival (RFS). All statistical analyses were two-sided with significance defined as P < 0.05.Results: For the entire cohort, the median follow-up OS period was 43.2 months. Tumor size, LVI, lymph node status, and treatment factors (operation type, chemotherapy, and hormone therapy) differed among subtypes with respect to OS and RFS. The highest incidence of LVI positivity (26.4% vs. 26.9%, respectively) and lymph node involvement (39.7% vs. 36.4%, respectively) occurred in the luminal B and luminal HER2 subtypes. There were significant differences in the OS and RFS rates according the LVI among the BCS. On multivariate analysis, there were significant differences in OS according to the status of lymph node-negative and LVI-positive in the luminal HER2 subtype, as well as lymph node-positive and LVI-positive in the triple negative (TN) subtype. There were also significant differences in RFS according to the status of lymph node-negative and LVI-positive in the luminal A subgroup.Conclusions: LVI in BCS was an important prognostic factor for OS and RFS. LVI and lymph node status were important prognostic factor for OS and RFS among BCSs. There were significant differences in OS according to the lymph node-negative and LVI-positive in the distribution of luminal HER2, the lymph node-positive, and LVI-positive in the distribution of TN. There were also significant differences in the RFS according to the lymph node-negative and LVI-positive in the luminal A.

Keywords

• Breast cancer subtypes
• lymphovascular invasion
• lymph node status
• overall survival
• recurrence-free survival