HER2 Equivocal Status in Early Breast Cancer Is Not Associated with Higher Risk of Recurrence

AIM: The primary aim of the study was to assess the association between risk of recurrence and HER2 equivocal gene status through immunohistochemistry in patients with early breast cancer.PATIENTS AND METHODS: We retrospectively analyzed clinical and pathological data of 455 consecutive patients with early breast cancer (BC) who were HER2(+) and had a HER2/CEP17 ratio <2.0, who underwent surgery at the European Institute of Oncology after 2007. The role of HER2/CEP17 ratio on recurrence-free survival was assessed with univariate and multivariate Cox regression models.RESULTS: We found no significant association between risk of recurrence and HER2 equivocal testing in patients with early breast cancer. In subgroup analysis, a significant interaction between HER2/CEP17 ratio and nodal involvement was observed (p=0.02).CONCLUSION: Patients with HER2 equivocal status have no significantly higher risk of recurrence.