Trastuzumab use in breast cancer: clinical issues.

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.