HER2 positive accounts for 6-10% of new cases of breast cancer.
Locally advanced breast cancer is generally associated with a poor prognosis and may be inoperable on presentation or require a mastectomy.
Preoperative systemic therapy used to treat subclinical micrometastatic disease and increase the rate of down staging is increasingly used to promote a successful surgical resection.
Preoperative systemic therapy provides information regarding the responsiveness of the tumor to systemic
HER2 amplification or overexpression is present in approximately 20% of early breast cancers and 35% of locally advanced breast cancers, and has been associated with a poor prognosis.