Radiotherapeutic management of brain metastases in patients with breast cancer: a narrative review.

Background and Objective: The incidence of brain metastasis (BM) has increased alongside improved survival among breast cancer patients. Brain metastasis in breast cancer (BCBM) patients pose a significant challenge due to the complexity and heterogeneity of the disease. This review summarizes the evidence and advances in radiotherapeutic management of BCBM and provides subtype-specific practice recommendations as a consensus from the Chinese Society of Clinical Oncology-Breast Cancer (CSCO-BC) committee. Methods: A comprehensive literature search was conducted across five databases (PubMed/MEDLINE, Web of Science, ClinicalTrials.gov, Scopus, and Google Scholar) from January 2009 to November 2025, focusing on the role of local treatment (primarily surgery and radiotherapy) for BCBM. Key Content and Findings: Current treatments for BCBM include surgery, radiotherapy, systemic therapy, and combination treatments to maximize the control of BM. Radiotherapy plays a crucial role in the management of BCBM, either as a standalone treatment or in combination with systemic therapy. Postoperative stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) has been demonstrated to improve prognosis and possibly reduce radiation necrosis when compared with surgery or stereotactic radiation alone. Meanwhile, the literature indicates the promising value of preoperative SRS/FSRT with minimal toxicity profile. SRS/FSRT has sufficient evidence of efficacy supporting its use in selected patients with oligometastatic or multiple BM. For large lesions, FSRT and staged SRS (SSRS) represent viable alternative treatment options, offering effective tumor control and reduced risk of radiation-related complications for patients who are not eligible for surgery. The optimal timing of radiotherapy, particularly for human epidermal receptor 2 (HER2)-positive or HER2-low expression disease, remains a topic of interest and under investigation. We propose a dedicated management algorithm for HER2-positive BCBM and address the specific considerations of this subtype. Treatment decision should involve discussions among a multidisciplinary team and patients, carefully weighing the risks and benefits of each treatment option to strive for prolonging survival while maintaining quality of life. Conclusions: This review highlights the importance of radiotherapy in the management of BCBM and provides evidence-based recommendations. Future research should focus on optimizing treatment protocols and investigating the optimal timing of radiotherapy across different subtypes.