Background: To characterize the incidence, treatment 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 to 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 or triple-negative diseases or with extensive extracranial metastases. First-line TKI and multidisciplinary treatment helped to extend survival.

Citation Format: Yiqun Li, Qiao Li, Hongnan Mo, Xiuwen Guan, Shaoyan Lin, Zijing Wang, Yimeng Chen, Ye Zhang, Dainan Zhang, Shanshan Chen, Ruigang Cai, Jiayu Wang, Yang Luo, Ying Fan, Peng Yuan, Pin Zhang, Qing Li, Fei Ma, Binghe Xu. Incidence, treatment and survival of patients with brain metastases at initial metastatic breast cancer diagnosis: A real-world experience in national cancer center, China [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-87.