Prognostic factors and survival outcome of brain metastases in breast cancer patients: A retrospective analysis.

e14005 Background: Brain metastasis (BM) is an increasingly complicated issue in breast cancer (BC) patients, occurring in approximately 10% to 30% of cases. BM is associated with poor prognosis with less responsiveness to systemic therapies. This study aims to explore the prognostic factors and survival outcomes for patients with BM from BC. Methods: This retrospective cohort study included female BC patients diagnosed with BM and treated at King Fahad Medical City hospitals from May 2018 to May 2023. Data were collected from electronic medical records, including variables such as age at BM diagnosis, Eastern Cooperative Oncology Group (ECOG) , tumor grade, histological subtypes, and treatment details. Multiple imputation was used to handle missing data. Statistical analyses, including univariate and multivariate Cox regression of the prognostic factors, were performed to determine the predictors of overall survival (OS). Results: A total of 136 were enrolled in the study. More than half of patients (61.8%) were aged 50 years or less. Twenty-six (19.4%) patients had triple negative BC, whereas 26.9% of the study participants had hormone positive BC. Regardless of the hormone status, more than half of the BC patients (53.7%) had HER2-positive status. Of all BMs, 72.3% presented metachronously. Brain metastasectomy was performed in 26.5% of the participants, while most of them (88.1%) received radiation therapy. Mean (SD) overall survival (OS) was 26.92 (18.25) months. The univariate analysis revealed that invasive lobular carcinoma (ILC) (HR=0.067, P =0.013), longer interval between BC diagnosis and BM occurrence (HR=0.974, P= 0.006) brain metastasectomy (HR=2.422, P= 0.004), and stereotactic radiotherapy (SRT) (HR=2.326, P =0.002) were associated with longer OS and good prognosis of BM. In multivariate analysis, the time interval between BC diagnosis and development of BM (HR=0.977, P= 0.019) and the histological types of BC (HR=0.031, P= 0.002) were independent prognostic factors for survival outcome. Conclusions: Although BM secondary to BC is associated with poor prognosis, factors such as brain metastasectomy, SRT, longer interval between primary BC diagnosis and BM occurrence, and ILC status improve the survival outcomes and prognosis of the disease. Additional studies are recommended to investigate the association between multiple prognostic factors and different treatment modalities for further improvement for BC patients with BM. The time from breast diagnosis to brain metastasis occurrence and the overall survival time of the study participants. Variable Mean Standard deviation Time to distant relapse (months) 18.03 14.37 Overall survival (OS) (months) 26.92 18.25