Systemic treatment for early HER2-positive breast cancer

HER2: human epidermal growth factor receptor 2; T-DM1: ado-trastuzumab emtansine; MRI: magnetic resonance imaging.
* Radiographic assessment typically includes mammography and ultrasonography, with or without MRI.
¶ Surgical resection may consist of breast-conserving surgery or mastectomy, depending on patient preference, tumor features, and response to therapy, if neoadjuvant treatment was administered.
Δ Preferred chemotherapy regimens include docetaxel/carboplatin as well as doxorubicin/cyclophosphamide, followed by a taxane. Further details and other options are discussed in UpToDate content on neoadjuvant therapy for patients with HER2-positive breast cancer.
◊ Radiation, if indicated, may be administered concurrently with anti-HER2 therapy (ie, trastuzumab, pertuzumab, or TDM-1, as indicated).
§ Chemotherapy selection is guided by results from surgical pathology. For node-negative tumors <2 cm, paclitaxel alone is an appropriate choice for chemotherapy. For larger or node-positive tumors, preferred chemotherapy regimens are according to the footnote above.^Δ Pertuzumab is usually added for tumors that are >2 cm or node positive.
¥ Endocrine therapy, if indicated, is administered concurrently with adjuvant anti-HER2 therapy (ie, trastuzumab, with or without pertuzumab; or T-DM1), after completion of any indicated adjuvant chemotherapy. While endocrine therapy may be administered concurrently with radiation, our approach is to delay until after completion, for those who will be treated with adjuvant radiation. Duration and choice of endocrine therapy are discussed in UpToDate topics on adjuvant endocrine therapy for hormone receptor-positive breast cancer.