Brain metastases in patients who receive trastuzumab-containing chemotherapy for HER2-overexpressing metastatic breast cancer.

BACKGROUND: Recently, a high rate of brain metastases has been reported among patients with human epidermal growth factor receptor (HER2)-overexpressing metastatic breast cancer who were treated with trastuzumab. The present study examined risk factors for the development of brain metastasis in patients with HER2-overexpressing breast cancer who were treated with trastuzumab.
METHODS: We retrospectively reviewed 204 patients with HER-2-overexpressing breast cancer who were treated with a trastuzumab-containing regimen between 1999 and 2006. Patients with clinical symptoms were diagnosed as having brain metastases when brain magnetic resonance imaging (MRI) or a computed tomography (CT) scan revealed positive findings for brain metastases. The median follow-up time of this cohort was 53.6 months.
RESULTS: Among the patients who received a trastuzumab-containing regimen, 74 patients (36.3%) developed brain metastases. The median survival from the diagnosis of brain metastases was 13.5 months (95% confidence interval [CI], 12.2-14.7 months). The median time interval between the beginning of trastuzumab treatment and the diagnosis of brain metastases was 13.6 months (range, 0.0-45.8 months). Among patients with brain metastases, the median overall survival period was 39 months. A multivariate logistic regression analysis showed that age (<or=50 years), recurrent breast cancer, and liver metastases were significant risk factors for the development of brain metastases.
CONCLUSION: Patients with HER2-overexpressing breast cancer treated with trastuzumab had a high incidence of brain metastases (36.3%). Routine screening for brain metastases 1 year after the start of trastuzumab treatment, may be warranted in younger patients (</=50 years) who had recurrent breast cancer with liver metastases.