# Surgical treatment of multiple breast cancer brain metastases: clinical characteristics and factors impacting postoperative survival

## TL;DR

This study examines the surgical treatment of multiple breast cancer brain metastases and finds that survival is not significantly worse compared to single metastases, especially with additional therapies.

## Contribution

The study identifies specific clinical factors and treatment approaches that impact survival in patients with multiple breast cancer brain metastases.

## Key findings

- Patients with multiple brain metastases were more likely to have HER2-positive breast cancer and hepatic metastases.
- Adjuvant radiotherapy and trastuzumab treatment were associated with longer postoperative survival in multiple brain metastasis patients.
- There was no significant difference in survival between patients with single and multiple brain metastases.

## Abstract

Breast cancer (BC) is one of the most common primary tumor entities that develop brain metastases (BM) during disease progression. Multiple BM are associated with poorer prognosis, but various surgical, radiotherapeutic and systemic treatment approaches improve survival. We aimed to identify prognostic factors and evaluate the overall survival following BM surgery in patients with multiple BCBM.

All metachronous metastasized female patients with resected BCBM at our institution between 2008 and 2019 were included. Data on clinical, radiologic, and histopathologic parameters were recorded and analyzed using univariate and multivariate regression models.

Among the 93 patients included in the final analysis, 30 individuals presented with multiple BM. Compared to patients with single BM, those with multiple BM were more likely to have infratentorial BM (adjusted odds ratio [aOR] 3.35, 95% confidence interval [CI] 1.03–10.83, p = 0.044), HER2(human epidermal growth factor receptor 2)-positive BC (aOR 3.93, 95% CI 1.23–12.53, p = 0.021) and hepatic metastases (aOR 5.86, 95% CI 1.34–25.61, p = 0.019). There was no significant difference in postoperative survival between individuals with multiple (median: 12.5 months) and single BM (17.0 months, p = 0.186). In the multivariate Cox regression analysis, adjuvant radiotherapy (adjusted hazard ratio [aHR] 5.93, 95% CI 1.06–33.26, p = 0.043) and trastuzumab treatment (aHR 4.95, 95% CI 1.72–14.25, p = 0.003) were associated with longer postoperative survival multiple BCBM patients.

BC patients with multiple BM show remarkable postoperative survival, particularly if combined with adjuvant radiotherapy. Our data justify the surgery of multiple BCBM in patients with appropriate clinical condition and feasible location of BM.

The online version contains supplementary material available at 10.1007/s11060-025-05048-3.