MRI-defined dissemination patterns in leptomeningeal metastases—association with survival and impact of clinical and treatment factors in a single-center cohort

Abstract Background Leptomeningeal disease (LMD) is associated with poor prognosis and clinical heterogeneity. We investigated whether MRI-defined dissemination patterns are associated with overall survival independent of clinical and treatment-related factors. Methods We performed a single-center retrospective cohort study of patients with LMD treated between 2012 and 2025 using an institutional registry. LMD was classified according to EANO–ESMO criteria, including MRI-defined subtypes: linear (A), nodular (B), combined linear and nodular (C), and no neuroimaging evidence except hydrocephalus (D). Overall survival (OS) was analyzed using Kaplan–Meier methods and Cox regression models. Results Overall survival was evaluable in 96 of 98 patients; 94 patients died and 2 were censored. Median overall survival was 1.93 months (95% CI, 1.40–2.53). OS differed across MRI-defined subtypes (log-rank p = 0.006), with the longest survival in nodular LMD (type B, 3.23 months). MRI type B (nodular) versus types A, C, and D was associated with longer OS in univariable analysis (HR 0.61, p = 0.048), but not in multivariable analysis (HR 0.78, p = 0.376). Higher Karnofsky Performance Status, radiotherapy after LMD, and systemic therapy after LMD were independently associated with longer OS. In a sensitivity analysis additionally accounting for treatment era and primary tumor group, type B remained not independently associated with OS (HR 0.68, p = 0.180). Conclusions MRI-defined LMD phenotype was associated with survival in unadjusted analyses but provided limited independent prognostic information after multivariable adjustment. It should be interpreted as part of multimodal disease characterization rather than as a standalone prognostic marker.