OBJECTIVES: Breast cancer is the second most common cause of death for women behind lung cancer, and overexpression of HER2 found in approximately 15-20% of all breast cancers. Trastuzumab is a recombinant monoclonal antibody against HER2, has clinical activity in advanced breast cancer that overexpresses HER2.

METHODS: Clinical trials which included Trastuzumab as an intervention for patients with HER2 positive Breast cancer were identified from 2011 to 2017 in databases such as, Cochrane, and MEDLINE (via PubMed). No language restrictions were applied. Two researchers independently reviewed studies using the Cochrane methodology for systematic reviews. Outcomes of interest included progression-free survival (PFS), Disease free survival (DFS), overall survival (OS), overall response rate (ORR), and safety.

RESULTS: A total of 105 potentially relevant studies were screened. Five clinical trials involving 7768 patients with HER2 positive Breast cancer were included. Overall 1892 patients were received Trastuzumab. The combination of Trastuzumab with Pertuzumab plus Docetaxel significantly prolonged progression-free survival, with no increase in cardiac toxic effects when used as first-line treatment for HER2-positive metastatic breast cancer. The addition of 1 year of adjuvant trastuzumab significantly improved disease-free and overall survival among women with HER2-positive breast cancer. The addition of trastuzumab to paclitaxel after doxorubicin and cyclophosphamide in early-stage HER2-positive breast cancer results in a substantial and durable improvement in survival as a result of a sustained marked reduction in cancer recurrence. Adjuvant trastuzumab improves RFS of patients treated with TX-CEX or T-CEF. Very few patients had cardiac failure.

CONCLUSIONS: Trastuzumab is an important treatment option for patients with HER2 positive Breast cancer. Trastuzumab improved overall survival and progression-free survival in HER2-positive women with metastatic breast cancer. Provides good survival benefit with minimal adverse events. However, the results have to be interpreted cautiously due to limited number of trials available.