NEIM-13 THE PROGNOSTIC ROLE OF VENTRICULAR SIZE AND ITS DYNAMICS IN PATIENTS WITH LEPTOMENINGEAL METASTASIS FROM SOLID TUMORS

BACKGROUND: Hydrocephalus is a common radiological sign in patients with leptomeningeal metastasis (LM) from solid tumors and can be assessed using the Evans index (EI) with high interrater agreement. Here we explored the prognostic value of ventricular size at diagnosis and during the disease course of LM. METHODS: We assembled a cohort of 113 adult patients with a diagnosis of LM from solid extra-CNS tumors and explored the association of ventricular size assessed by the EI at diagnosis, of its modification between diagnosis and evaluation at first follow-up and at first progression, with outcome. RESULTS: Median age was 58.2 years (interquartile range (IQR) 46.1-65.7), 41 patients (36%) were male, the most frequent cancers were lung cancer (n=39, 35%), breast cancer (n=36, 32%) andmelanoma (n=23, 20%). The median EI at baseline was 0.28 (IQR 0.26-0.31), the EI value was 0.27 or more in 67 patients (59%) and 0.30 or more in 37 patients (33%). At LM progression, an increase of EI of 0.01 or more was noted in 18 of 34 patients (53%). The median overall survival was 2.9 months (IQR 1-7.2). Patients with a baseline EI of 0.26 or less had a longer survival than those with an EI of 0.27 or more (5.3 months, IQR 2.4-10.8, versus 1.3 months, IQR 0.6-4.1) (p=0.006). Among patients with follow-up scans available, median overall survival was 9.7 months (IQR 5.6-21.4) for patients with stable or decreased EI at first follow-up as opposed to 6.4 months (IQR 3.2-10.5) for those with an increase in the EI (p=0.292). CONCLUSION: The EI at baseline is prognostic in LM. An increase of EI during the follow-up is associated with inferior LM-PFS. An independent validation cohort with larger sample size and evaluation of confounding factors will help to better define the role of EI assessments in LM.