Case report: Systemic T-DXd and bevacizumab plus local therapy prolongs survival in breast cancer leptomeningeal metastasis: a case series and literature review

Leptomeningeal metastasis from breast cancer has a low incidence but an extremely poor prognosis. With the development of antitumor therapies, the survival of patients with metastatic breast cancer has been significantly prolonged. However, due to the presence of the blood–brain barrier, intracranial metastasis has become increasingly prominent, and the incidence of leptomeningeal metastasis is gradually rising, warranting greater attention and improvement. Currently, there is a lack of effective treatment options for leptomeningeal metastasis, and no unified diagnostic or therapeutic standards exist. This case series reports seven breast cancer patients with leptomeningeal metastasis who received trastuzumab deruxtecan combined with whole-brain radiotherapy; four of them also received bevacizumab and intrathecal chemotherapy. In these four patients, the addition of bevacizumab and intrathecal therapy was associated with rapid alleviation of central nervous system symptoms and a numerically longer overall survival (9.0–20.2 months) compared with historical data. No severe or fatal adverse events were observed. Additionally, through a review of the literature, we summarize the current status, diagnosis, treatment, prognosis, and potential future directions of leptomeningeal metastasis from breast cancer, aiming to provide reference for the management of these patients.