[Brain metastases in breast cancer: Diagnosis and management]

Breast cancer is the second most common cause of brain metastases, after lung cancer. The risk of developing brain metastases varies according to the molecular subtype of breast cancer, with a higher incidence for triple-negative or HER2-positive cancers. The discovery of brain metastases, whether synchronous or metachronous, is a turning point in oncology management, and requires discussion at a neuro-oncology multidisciplinary consultation meeting to assess the value and modalities of local treatment by surgery and/or radiotherapy (stereotactic or total brain). Systemic treatments also play a major role in the control of breast cancer brain metastases. The most abundant literature on brain metastases concerns HER2-positive breast cancers, with robust data on the intracerebral efficacy of tyrosine kinase inhibitors (tucatinib, neratinib) and drug-conjugated antibodies (trastuzumab deruxtecan). The size of the brain metastases, whether they are stable or progressive, any previous irradiation, whether the brain involvement is symptomatic or not, the extracerebral evolution of the disease, the patient's general condition and the systemic options available must all be taken into account before deciding on a therapeutic strategy. This article does not deal with the specific management of leptomeningeal disease, which will be the subject of a separate article.