What is trastuzumab (Herceptin®)?
Trastuzumab is a drug used to treat a type of breast cancer called ‘HER2-positive breast cancer’. ‘HER2-positive’ means that the breast cancer cells have higher than normal levels of a protein – called the HER2 protein – on their surface. Trastuzumab is an antibody that works by attaching itself to HER2-positive cancer cells and stopping the cells from growing and dividing.
How do I know if I am HER2-Positive?
About one in five patients diagnosed with breast cancer have HER2-positive breast cancer. Your pathology report shows whether your breast cancer cells are HER2-positive. There are two ways for a pathologist to test for HER2:
IHC (immunohistochemistry) is a test that measures the amount of HER2 protein on the cells ISH (in-situ hybridisation) is a test that measures the amount of the HER2 gene in the cells; there are two types of ISH tests.
All breast cancer cells have some HER2 protein, but only an IHC score of 2+ (with subsequent confirmation by ISH test), IHC score of 3+ or a positive ISH result shows that the breast cancer cells are HER2-positive. Talk to your doctor about whether your cancer is HER2-positive. You can also ask your doctor for a copy of your pathology report. If your breast cancer cells are not HER2 postive, trastuzumab will have no benefit for you.
Trastuzumab for the treatment of early breast cancer and metastatic breast cancer
National Breast and Ovarian Cancer Centre has developed some information to help you understand and make decisions about the use of trastuzumab (Herceptin®) for the treatment of:
Early breast cancer
pdf (111kb) and
Metastatic breast cancer pdf (111kb)
The information has been developed by a multidisciplinary working group and is based on National Breast and Ovarian Cancer Centre guidelines
Recommendations for use of trastuzumab (Herceptin®) for the treatment of HER2-positive breast cancer
pdf (673kb).
