Clinical diagnosis and treatment of breast cancer with brain metastases and establishment of a prognostic model: a 10-year, single-center, real-world study of 559 cases

BACKGROUND: This study involved a retrospective analysis of 559 metastatic breast cancer (MBC) patients with brain metastasis (BM). We aimed to establish the effectiveness of different preferred treatment methods and factors affecting overall survival following BM diagnosis (BMOS) and explore the feasibility of systemic treatment for MBC patients with BM. METHODS: Univariate and multivariate analyses were used to assess the efficacy of different preferred treatments and other factors associated with BMOS, and a nomogram was then established based on the results of the univariate analysis. RESULTS: Patients that initially received systemic drug therapy exhibited a clinical benefit rate (CBR) of 43.9% and an intracranial disease control rate (DCR) of 80.6%. The median time between BM diagnosis and the requirement for local intracranial treatment due to worsening disease status was 10.0 months for these patients (95% CI: 7.811–12.189 months). The median follow-up was 28.0 months, and the median BMOS was 16.0 months. Following BM diagnosis, the systemic drug treatment group had a better outcome than the local brain treatment group, with a respective median BMOS of 22.0 and 16.0 months (χ(2)=7.743, P=0.005). At the time of BM diagnosis, the median BMOS for patients without neurological symptoms diagnosed by regular screen was significantly longer than that of patients with neurological symptoms (18.0 vs. 13.0 months, respectively; χ(2)=11.371, P=0.001). Based on these analyses, a nomogram was constructed that incorporated disease-free survival (DFS), Karnofsky performance status (KPS), molecular subtype, number of extracranial metastases, BM location, number of BMs, neurological symptoms, and the preferred treatment approach, with a prediction probability (c-index) value of 0.76. CONCLUSIONS: Systemic drug treatment has a beneficial effect on brain lesions, and effective treatment delays the need for local intracranial treatment. Cranial magnetic resonance imaging (MRI) screening can detect asymptomatic BM in MBC patients (particularly those with HER2−positive or triple-negative disease), offering these patients an opportunity to undergo systemic drug therapy, thereby prolonging their survival. To our knowledge, this is a well-fitted nomogram including current treatment and medical examination strategies to predict BMOS probability that offers value as an adjunct for the prognostic evaluation of MBC-BM patients.