Sinusal localization of nodal micrometastases is a prognostic factor in breast cancer

Background: Breast cancer micrometastases are frequently found during pathological examination of sentinel lymph nodes and complete axillary lymph node dissection. Despite this, their clinical relevance is still debated. The aim of this study is to investigate features that affect disease-free survival (DFS) and overall survival (OS) in patients with nodal micrometastases from breast cancer. Material and methods: We retrospectively investigated the outcome of 122 patients with nodal micrometastases from breast cancer followed up for 60 months. Results: At univariate analysis, worse DFS was related to features of primary tumor (multifocality P = 0.002; size > 2 cm, P = 0.022; grade P = 0.022; absence of estrogen P < 0.001 and progesterone P < 0.001 receptors; HER-2 overexpression P = 0.006; vascular invasion P = 0.039; proliferative fraction >= 20% P = 0.034) and micrometastases (sinusal localization P = 0.010). Among the above-mentioned features, two were strongly associated with worse DFS in the multivariate model, i.e. negative receptorial status [hazard ratio (HR) = 11.24, 95% confidence interval (CI) 4.06-31.09; P < 0.001] and sinusal localization of micrometastasis (HR = 3.66, 1.18-11.36; P = 0.025). The OS was influenced by multifocality (P < 0.001) and receptor status (P = 0.005). Conclusion: Our results indicate that in patients affected by breast cancer, in addition to the well-known pathological features of primary tumor, sinusal localization of micrometastasis strongly impacts on the prognosis.