Breast cancer brain metastases: Clinical and prognostic characteristics of different biological subtypes

Objective: To analyze the clinical characteristics and survival depending on biological subtypes in breast cancer patients with brain metastases (BM). Methods: A retrospective analysis was performed on 152 breast cancer patients with BM admitted to the Cancer Institute & Hospital, Chinese Academy of Medical Sciences from January 2003 to December 2012. Depending on the biological characteristics, these patients were divided into three subtypes; Luminal, human epidermal growth factor receptor 2 (HER-2)-overexpressing, and triple-negative subtypes. The clinicopathological characteristics, recurrence status, and prognostic factors were analyzed at the initial diagnosis. The systemic therapy after BM was further studied. Results: Among the 152 patients, the number of Luminal, HEK-2-overexpressing, and triple-negative breast cancer (TNBC) subtypes were 60, 53, and 39 cases, respectively. The median time from first recurrence to BM of all patients was 7.3 months, the median time of Luminal, HER-2-overexpressing, and TNBC subtypes was 11.0 months, 9.6 months, and 5.5 months, respectively (P < 0.001). Compared with the TNBC subtype, BM occurred later in the HER-2-overexpressing subtype (P < 0.001). In the HER-2-overexpressing subtype, trastuzumab could delay the occurrence of BM in advanced breast cancer patients (17.1 vs. 1.7 months, P <0.001, 95%CI5.21-13.98). The median time of overall survival (OS) in the whole group was 56.5 months (7.5-240.2 months, 95%CI 52.6-60.4). The median survival time of Luminal, HER-2-overexpressing and TNBC subtypes was 70.9 months, 53.9 months, and 40.9 months, respectively (P = 0.013). The median survival time of after BM was 11.5 months in the whole group, and the median survival time of Luminal, HER-2-overexpressing and TNBC subtypes was 11.2 months, 12.7 months, and 11.6 months, respectively, with a difference of no statistical significance. Compared with non-BM as the first site, the patients with BM as the first site had a longer survival (14.8 months vs. 8.0 months, P = 0.001). Systemic therapy could prolong the survival after BM. The median survival of chemotherapy, chemotherapy in combination with trastuzumab, and without systemic therapy was 13.6 months, 19.0 months, and 6.5 months, respectively (P = 0.043). Conclusions: The survival after BM is influenced by biological subtypes. Compared with the Luminal subtype, brain meatastases occurr earlier in HER-2-overexpressing and TNBC subtypes. Trastuzumab can delay the occurrence of BM from advanced breast cancer, and systemic therapy can improve the survival of patients after brain metastasis.