Incidence, risk factors and survival of patients with brain metastases at initial metastatic breast cancer diagnosis in China

PURPOSE: To characterize the incidence, risk factors and survival of patients with brain metastases at initial diagnosis of metastatic breast cancer (MBC) in China. METHODS: The China National Cancer Center database was used to identify 2087 MBC patients diagnosed between 2003 and 2015. Clinicopathological features, treatment and survival information were extracted. Multivariable logistic and Cox regression were performed to determine factors predictive of brain metastases at MBC diagnosis and survival, respectively. RESULTS: Brain metastases occurred in ninety patients (4.3%) at MBC diagnosis, and in 27 patients (2.5%), 42 patients (7.2%) and 21 patients (5.2%) with hormone receptor positive, human epidermal growth factor receptor 2 negative (HR + HER2-), HER2-positive and triple negative breast cancer (TNBC), respectively. HER2-positive subtype (OR = 2.38; 95% CI 1.40–4.04; p < 0.0001), TNBC subtype (OR = 1.89; 95% CI 1.02–3.51; p = 0.005), and metastases to all three sites of bone, liver and lungs (OR = 3.23; 95% CI 1.52–6.87; p = 0.002) were shown to increase the risk of BM at MBC diagnosis. Median survival after BM was 23.7 months. First-line tyrosine kinase inhibitors (TKI) improved survival compared to trastuzumab-based regimen (44.9 vs 35.4 months, p = 0.09). Factors that independently decreased BM death risk were ECOG<2, brain metastases only and multidisciplinary treatment. CONCLUSION: HER2-positive and TNBC subtypes have a higher incidence of BM at initial MBC diagnosis. Brain screening might be considered in patients with HER2-positive disease at MBC diagnosis, and further prospective randomized study is warranted.