The Breast : official journal of the European Society of Mastology
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The introduction of trastuzumab as adjuvant treatment for patients with HER2-positive breast cancer changed the natural course of early-stage disease. Currently, one year of trastuzumab given concurrently with a taxane and following an anthracycline regimen is the preferred standard of care in Europe. The first attempt to escalate this approach, though the implementation of dual HER2 blockade with lapatinib added to trastuzumab, as assessed by the ALTTO trial, failed to improve further clinical outcomes; clinical assessment of the adjuvant trastuzumab/pertuzumab regimen is still ongoing in the APHINITY trial. ⋯ Despite the clear association of pCR achieved through neoadjuvant trastuzumab-based chemotherapy with clinical outcome, results from neoadjuvant trials have not been always consistent with what was seen in the adjuvant setting. Similarly, inconsistent results have been reported for the predictive ability of alterations affecting the PI3K signaling pathway or the quantification of tumor infiltrating lymphocytes. In the era of personalized oncology, rigorous translational and clinical collaborative efforts are needed to further advance the field of treatment of patients with HER2-positive breast cancer.