Safe de-escalation of chemotherapy in HER2-positive early breast cancer

Targeted therapy for HER2-positive early and metastatic breast cancer has been one of the cancer success stories of the 21st century, as part of a paradigm shift towards precision cancer medicine. The Early Breast Cancer Trialists' Collaborative Group overview showed that adjuvant trastuzumab when added to chemotherapy improved long-term outcomes for patients with an absolute benefit of 9·0%.1 In addition, anti-HER2 directed therapy has altered the shape of the Kaplan–Meier survival curves, so not only has the frequency of metastatic relapse dramatically decreased, but the annual hazard rate of relapse in the first 5 years is also considerably lower when compared with the pre-trastuzumab era.