Future directions in the adjuvant treatment of breast cancer: the role of trastuzumab

Abstract

Current evidence shows that adjuvant cytotoxic or hormonal therapy increases the disease-free and overall survival of patients. The analysis by the Early Breast Cancer Trialists' Collaborative Group (EBCTCG) showed that anthracycline/cyclophosphamide (AC)-containing regimens are more effective than those without AC, providing an 11% greater reduction in the risk of death compared with non-AC-containing regimens. In addition, paclitaxel and docetaxel have significant anti-tumor activity in previously treated patients and sequential treatment with paclitaxel may further reduce the risk of recurrence and improve survival. Tamoxifen is effective in reducing the risk of recurrence and death in patients with estrogen receptor (ER)-positive tumors. The addition of tamoxifen to combination chemotherapy in patients with ER-positive tumors further reduces the risk of recurrence and improves survival. Debate on the effectiveness of tamoxifen in HER2-positive patients is currently underway. A number of trials are in progress or planned to investigate the use of the anti-HER2 monoclonal antibody trastuzumab (Herceptin) in the adjuvant setting. These include a National Surgical Adjuvant Breast and Bowel Project (NSABP) adjuvant trial (AC --> paclitaxel vs. AC --> paclitaxel + trastuzumab) and an Intergroup study (AC --> paclitaxel vs. AC --> paclitaxel + trastuzumab vs. AC --> paclitaxel --> trastuzumab). Results from these trials will determine whether this novel therapy has a survival benefit in early breast cancer.