Trastuzumab after Adjuvant Chemotherapy in HER2-Positive Breast Cancer

After surgical excision of early HER2-positive breast cancer and adjuvant chemotherapy, the administration of trastuzumab, a monoclonal antibody against HER2, was associated with longer disease-free survival than was observation. After surgical excision of early HER2-positive breast cancer and adjuvant chemotherapy, the administration of trastuzumab was associated with longer disease-free survival than was observation. Her2/ neu (hereafter referred to as HER2) belongs to a family of four transmembrane receptor tyrosine kinases that mediate the growth, differentiation, and survival of cells. 1 , 2 Overexpression of the HER2 protein, amplification of the HER2 gene, or both occur in approximately 15 to 25 percent of breast cancers, and are associated with aggressive behavior in the tumor. 3 , 4 Trastuzumab (Herceptin, Roche), a humanized monoclonal antibody against the extracellular domain of HER2, has been shown to benefit patients with HER2-positive metastatic breast cancer when administered weekly or every three weeks, alone 5 , 6 or in combination with chemotherapy. 7 , 8 Trastuzumab is . . .