Background: Overexpression of the epidermal growth factor 2 HER2 in breast cancer tissue is associated with shorter survival. Trastuzumab, a monoclonal antibody against HER2, can induce tumor responses when given alone and enhances the effectiveness of several chemotherapeutic agents.
Methods: The recent clinical data on outcomes regarding testing for HER2 overexpression and the tolerance, toxicity, and antitumor effects of trastuzumab are reviewed.
Results: Trastuzumab use is indicated either alone or with chemotherapy only in patients with IHC 3+ or FISH+ test results and survival is prolonged in patients with metastatic disease. Cardiac toxicity differs from anthracycline cardiac toxicity and is often reversible.
Conclusions: The safety and efficacy profile of trastuzumab in patients with metastatic disease has led to large-scale testing of addition of the intervention in the adjuvant setting.