The drug trastuzumab (Herceptin) has been used for many years to treat metastatic breast cancer. Now, it is also used to treat early stage breast cancer, including lymph node-positive and some lymph node-negative cancers.
Trastuzumab is a specially made antibody that targets cancer cells that have high amounts of a protein called HER2/neu on their surfaces. When attached to the HER2/neu protein, trastuzumab slows or stops the growth of the cancer cells. Studies show that chemotherapy plus trastuzumab cuts the risk of recurrence in half compared to chemotherapy alone among women with HER2/neu-positive cancers [53-55]. Trastuzumab is only used to treat HER2/neu positive cancers and has no effect on HER2/neu-negative cancers.
The HER2/neu status of a tumor is determined by testing tissue removed during a biopsy. About 20 percent of breast cancers are HER2/neu positive, meaning the test found a high number of HER2/neu proteins [56]. These breast cancers may be eligible for treatment with trastuzumab. All tumors should be tested for HER2/neu status. For more on this, see the Diagnosis section.
Trastuzumab use is linked to congestive heart failure, a serious heart condition. In clinical trials, two 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 [53,54]. Because of this risk, trastuzumab plus chemotherapy is most often recommended only 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.
Updated 10/20/09
