ERBB2 and breast cancer: The KATHERINE trial assessed the administration of trastuzumab emtansine (T-DM1) in patients with residual disease after neoadjuvant chemotherapy.12 Risk of invasive disease recurrence was reduced by 50% in patients who received post-neoadjuvant therapy with T-DM1, making this a new treatment standard.12 The personalized approach in the post-neoadjuvant setting clearly favors neoadjuvant systemic therapy (NAT) for HER2+ early breast cancer.