Clinical factors and association with treatment modalities in patients with breast cancer and brain metastases who develop leptomeningeal metastases

Purpose: Leptomeningeal metastases (LM) are an aggressive complication of metastatic breast cancer (MBC) with brain metastases (BM), with a short survival of weeks to months. Studies suggest that surgical resection of BM may increase the risk of LM, especially in infratentorial metastases. In this retrospective study, we examine this and other factors which may be associated with increased risk of LM. Methods: A database search at a single institution identified 178 patients with MBC and treated BM between 2007 and 2020. We collected demographic, clinical, radiographic, and other treatment data. LM was diagnosed by cerebrospinal fluid (CSF) cytology, neuroimaging, or both. Cox proportional hazards model was used. Results: After a median follow-up of 8.5 months, 41 out of 178 patients (23%) with BM developed LM. Median time to develop LM was 130 days. Mean age was 51.3 years. The number and size of the BM, hemorrhagic/cystic lesions, progressive/stable systemic disease, and extracranial metastases sites other than liver did not pose a higher risk of LM. Infratentorial lesions (HR = 5.41) and liver metastases (HR = 2.28) had a higher risk of LM. Patients who had any surgery did not have a higher risk for LM (HR 1.13). The LM group had a worse overall survival as compared to the non-LM group. Conclusion: Among MBC patients with BM, infratentorial BM and visceral liver lesions increase the risk of LM, whereas local treatment modalities such as surgery and radiation do not. These data imply that local treatment strategy should not differ based on potential risk for LM.