The drug trastuzumab (Herceptin) has been used for many years to treat metastatic breast cancer. Now, it is also used to treat early breast cancer, including lymph node-positive and some lymph node-negative cancers.
How does trastuzumab work?
Some breast cancers have high amounts of a protein called HER2/neu on the surface of the cancer cells (called HER2/neu-positive breast cancer). The HER2/neu protein is important for cancer cell growth. Trastuzumab is a specially made antibody that targets HER2/neu-positive cancer cells. When attached to the HER2/neu protein, trastuzumab slows or stops the growth of the cancer cells.
Testing for HER2/neu status
The HER2/neu status of a tumor is determined by testing tissue removed during a biopsy. All newly diagnosed breast cancers are tested for HER2/neu status.
About 15 to 20 percent of breast cancers are HER2/neu positive [65-66]. These breast cancers can be treated with trastuzumab.
Learn more about HER2/neu status.
Trastuzumab for the treatment of HER2/neu-positive breast cancer
Studies show that chemotherapy plus trastuzumab cuts the risk of recurrence in half compared to chemotherapy alone among women with HER2/neu-positive cancers [67-69].
Trastuzumab is only used to treat HER2/neu positive cancers and has no role in the treatment of HER2/neu-negative cancers.
Risks related to trastuzumab
Trastuzumab use is linked to congestive heart failure, a serious heart condition. In clinical trials, one to four percent of those treated with chemotherapy plus trastuzumab had heart failure, compared to fewer than one percent of those treated with chemotherapy alone [67-68,70]. This risk of heart problems may be higher with chemotherapy regimens that contain an anthracycline than with regimens without an anthracycline [166].
Because of the risk of heart problems, trastuzumab is most often only recommended for people with lymph node-positive cancer or node-negative cancer with tumors larger than one centimeter.
Your heart will be checked before and during treatment with trastuzumab to help ensure there are no problems.
To learn more about trastuzumab, visit the National Institutes of Health’s Medline Plus website.
Updated 10/18/11
