Objective: The aim of this study was to assess whether trastuzumab usage is a risk factor for the development of brain metastasis (BM) in human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) and factors affecting survival after development of BM.
Materials and methods: One hundred thirty-two patients treated with (treatment group) or without trastuzumab (control group) with brain metastasis were retrospectively analyzed.
Results: Ninety of the 132 HER2-positive MBC patients were in the treatment group and 42 were in the control group. BM was significantly increased in patients who were treated with trastuzumab in two or more lines (58.5 vs 24.1 %, p < 0.001). Trastuzumab and lapatinib usage after BM and age were independent prognostic factors for overall survival in univariate and multivariate analysis.
Conclusion: The risk for BM was increased in patients who were treated with trastuzumab in two or more lines. Using trastuzumab and lapatinib after BM and age were independent prognostic factors for time to death from BM.