Durable complete response in HER2-positive breast cancer: a multicenter retrospective analysis.

Purpose: Though advanced and metastatic epidermal growth factor receptor 2 (HER2)-positive disease is not curable, a small proportion of patients with HER2-positive metastatic breast cancer remain in prolonged complete remission with anti-HER2 treatment. We hypothesized that some cases of HER2-positive metastatic breast cancer may be curable. In this large, multicenter retrospective study, we aimed to assess the long-term outcomes for patients with a durable response to trastuzumab.