Recent advances and optimal management of human epidermal growth factor receptor-2-positive early-stage breast cancer

With the introduction of anthracycline-based regimens, 5-year survival rates have significantly improved in patients with early-stage breast cancer. With the addition of trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor-2 (HER2), improvements in overall survival have been observed among patients with advanced HER2-positive disease. Subsequently, lapatinib, an orally bioavailable small molecule dual HER2- and EGFR/HER1-specific tyrosine kinase inhibitor, received Food and Drug Administration (FDA) approval in combination with capecitabine for patients with advanced HER2+ breast cancer. Then, pertuzumab in 2012 and ado-trastuzumab emtansine in 2013 were approved in the US and elsewhere based on evidence showing an improvement in survival outcomes in patients with mostly trastuzumab naïve or trastuzumab-exposed metastatic disease. The FDA also approved 1 year of extended adjuvant neratinib after chemotherapy and a year of trastuzumab for HER2-positive breast cancer on the basis of the ExteNET trial. The clinical benefit demonstrated by those drugs in advanced disease has triggered several adjuvant and neoadjuvant trials testing them in combination with chemotherapy, but also without conventional chemotherapy, using single or dual HER2-targeting drugs. In this article, we review the current data on the therapeutic management of HER2-positive early-stage breast cancer in the adjuvant and neoadjuvant setting. We also review the data the efficacy and safety of anthracycline-based and nonanthracycline-based adjuvant chemotherapy regimens combined with trastuzumab, and optimum chemotherapy regimens in small HER2-positive tumors.