# A real-world study on clinical features and prognosis of Chinese breast cancer patients with brain metastases

## TL;DR

This study examines the clinical features and survival outcomes of Chinese breast cancer patients who develop brain metastases.

## Contribution

The study identifies distinct metastatic patterns and prognostic factors specific to breast cancer molecular subtypes in a real-world cohort.

## Key findings

- Luminal subtype correlates with bone metastases, HER2-positive with liver metastases, and luminal with leptomeningeal metastases.
- HER2-positive subtype and brain metastasis as first metastatic site are protective for survival, while leptomeningeal metastasis is a risk factor.
- Most patients received radiotherapy, and 81.52% had died after a median follow-up of 63.1 months.

## Abstract

This study aimed to analyze the clinical characteristics and prognosis of breast cancer (BC) patients with brain metastases (BM).

We performed a retrospective analysis of breast cancer patients with brain metastases (BCBM) in a real-world setting.

In a cohort of 249 breast cancer brain metastasis (BCBM) patients (all female; median age 46 years), molecular subtypes were distributed as follows: luminal (38.95%), HER2-positive (32.93%), and triple-negative (28.11%). Distinct metastatic patterns were observed: luminal subtype correlated with bone metastases (55.73%, p<0.001), HER2-positive with liver metastases (46.34%, p<0.001), and luminal with leptomeningeal metastases (19.59%, p=0.002). For CNS-directed treatment, 70.28% received radiotherapy (69.71% whole-brain radiotherapy, 30.28% stereotactic radiosurgery), while 23.69% received no local treatment. After median follow-up of 63.1 months, 81.52% had died. Multivariable analysis identified HER2-positive subtype and brain metastasis as first metastatic site as protective for overall survival after brain metastasis (OS-BM), while leptomeningeal metastasis were independent risk factors.

This study reveals distinct patterns of metastatic spread across breast cancer molecular subtypes and identifies key prognostic factors for survival after brain metastasis. The findings underscore the critical influence of tumor biology on disease progression and outcomes, highlighting the need for subtype-specific management strategies in BCBM patients.