Patients who have HER2 -positive cancer will be offered the monoclonal antibody, Trastuzumab (Herceptin). Herceptin interferes with the HER-2/neu receptor. HER-2 receptors are proteins or transmembrane receptors with tyrosine kinase activity and are overexpressed in approximately 20 percent of breast cancers. They are embedded in the cell membrane. The Protein stimulates cell proliferation. When HER-2 is over-expressed it causes cancer cells to reproduce uncontrollably.
Patients that have HER-2 positive breast cancer should be offered Herceptin as it will improve survival and reduce the risk of breast cancer recurrence. It has a risk of associated heart problems in approximately 2% of patients and patients routinely undergo ultrasounds of the heart during treatment with the drug.
Before the widespread use of Herceptin overexpression of HER2 was associated with high recurrence rates and increased mortality. HER2- positive breast cancers are more biologically aggressive compared to other breast cancer subtypes.
The introduction of Trastuzumab to treat HER 2- positive disease has been a true success of targeted therapy. Trastuzumab has improved cancer mortality in HER2-overexpressing tumors by 33 percent and it has also significantly reduced local recurrence. The use of Herceptin in HER-2 positive early stage and metastatic breast cancer has had major impact on survival and response rates.
Some women will be offered neoadjuvant therapy; that is some women will have chemotherapy or targeted therapy such as Herceptin, radiotherapy, or hormonal therapy or combination of these given before the breast cancer surgery. This is termed neoadjuvant therapy or treatment. It may also be referred to as preoperative therapy, induction therapy, or primary systemic therapy.