 But still is little known about the long-term outcome nor patterns of disease progression of HER2-positive MBC. A few case reports showed a prolonged complete remission in HER2-positive MBC under an anti-HER2 treatment trastuzumab, T-DM1, pertuzumab. These cases had some common characteristics such as negative hormone receptor status and metastasis to the live. Another hypothesis is a worse prognosis for patients with early development of CNS metastases. 