Efficacy and Safety of Adjuvant Docetaxel and Trastuzumab in Stage I HER2-positive Breast Cancer

HER2-positive breast cancer accounts for about 20% of invasive breast cancers and was historically associated with poor clinical outcomes. Trastuzumab, a humanized monoclonal antibody that binds HER2, improved the outcomes for patients with HER2-positive breast cancer. Four phase 3 randomized trials (HERA, the North Central Cancer Treatment Group N9831, the National Surgical Adjuvant Breast and Bowel Project B-31 and BCIRG006) involving more than 8000 patients showed that when trastuzumab was administered in combination with or after chemotherapy, the risk of recurrence was decreased by approximately 50% and overall survival improved. For patients with lymph node negative, early stage HER2-positive breast cancer, epirubicin/cyclophosphamide followed by docetaxel/trastuzumab (AC-TH) or docetaxel/carboplatin/trastuzumab (TCbH) adjuvant regimen is still widely used, although a smaller absolute benefit is expected. According to the long-term survival outcome of the Adjuvant Paclitaxel and Trastuzumab (APT) trial, patients with tumors measuring up to 3 cm in greatest dimension, negative axillary lymph node or with only micrometastasis, who received adjuvant paclitaxel 80mg/m2 weekly for 12 times plus 1 year trastuzumab, achieved a 3-year disease free survival (DFS) of 98.5%, 5-year DFS of 96.3%, 7-year DFS of 93.3%. The FDA compared the outcome of APT trial with external controls from previous clinical trials, both DFS and overall survival (OS) were similar. However, weekly regimen is quite inconvenient for patients, which also increased the patients'and social economic burdens in China. Docetaxel, a newly developed taxoid anticancer agent, works a comparable way to paclitaxel. In the clinical trial E1199, early breast cancer patients receiving adjuvant adriamycin and cyclophosphamide (AC) followed by docetaxel every 3 weeks achieved similar outcomes with AC followed weekly paclitaxel. In our study, a prospective, randomized, open-label, single-center clinical study is conducted to compare the efficacy and safety of adjuvant docetaxel plus trastuzumab (TH, q3w×4) and the classic regimen (PH, qw×12) in stage I HER2-positive breast cancer in Chinese population.