Dural Metastasis in Breast Cancer: MRI-Based Morphological Subtypes and Their Clinical Implications.

Purpose:To investigate the clinical factors associated with breast cancer (BRCA) dural metastases (DMs), their impact on prognosis compared to brain parenchymal metastases (BPMs) alone, and differences between DM subtypes, aiming to inform clinical decisions. Materials and Methods:We retrospectively analyzed 119 patients with BRCA with brain metastasis, including 91 patients with BPM alone and 28 patients with DM. Univariate and multivariate analyses were performed to compare the clinical characteristics between the two groups and within subtypes of DM. Overall survival after DM (OSDM) and the interval from DM to leptomeningeal carcinomatosis (LMC) were compared using Kaplan-Meier analysis. Results:DM was notably linked with extracranial metastasis, luminal-like BRCA subtype (p=0.033), and skull metastases (p<0.001). Multiple logistic regression revealed a strong association of DM with extracranial and skull metastases, but not with subtype or hormone receptor (HR) status. Patients with DM did not show survival differences compared with patients with BPM alone. In the subgroup analysis, nodular type DM correlated with HER2 status (p=0.044), whereas diffuse type DM was significantly associated with a higher prevalence of the luminal-like subtype (p=0.048) and the presence of skull metastasis (p=0.002). Patients with diffuse DM did not exhibit a significant difference in OSDM but had a notably shorter interval from DM to LMC compared to those with nodular DM (p=0.049). Conclusion:While the impact of DM on the overall prognosis of patients with BRCA is minimal, our findings underscore distinct characteristics and prognostic outcomes within DM subgroups.