Prognostic Value Of Pretreatment Mri In Breast Cancer Related Leptomeningeal Metastases

2067 Background: The National Comprehensive Cancer Network (NCCN) guidelines considers radiographic bulky disease as assesed by MRI as a negative prognostic factor in leptomeningeal metastases (LM). Our aim was to determine the prognostic value of pre-treatment MRI in patients with breast cancer (BC) related LM. Methods: We retrospectively evaluated pretreatment MRI in a cohort of 60 women with BC and LM to determine the correlation between CNS MRI abnormalities and survival. All images were reviewed by a neuroradiologist and a neuro-oncologist. Statistical analyses were performed using SAS software V9.3. Results: At LM diagnosis, patient median age was 56 (range, 35-81) and ECOG performance status was 0-2 in 64.5%. Breast cancers were invasive ductal carcinoma in 70.5%. Estrogen receptor and progesterone receptor were present in 71.5% and 56.5% respectively. 25% of tumors were HER2 positive and 16.5% were triple negative. Malignant cells were observed in the CSF in 64%. Brain MRI showed abnormalities consistent with LM in 73% including ; hydrocephalus (10% of all patients), focal (29%) or a diffuse (35.5%) linear leptomeningeal contrast enhancement (CE), subependymal CE (27%), sulci (35.5%), folia (46%) and cranial nerve (30.5%) CE and intracranial nodules (12.5%). Spine MRI revealed the following : linear focal (8.5%) or diffuse (54%) CE (71%) and subarachnoid nodules (16.5%). The cauda equina showed enhancement in 71% of patients. 91.5% of patients received intra-CSF chemotherapy, 59.5% systemic therapy and 18% radiotherapy. All but one patient died. Survival was less than 2 months in 33.5% and greater than 6 months in 36%. Median progression free survival (PFS) was 2.5 months (range, 0.03-3.3). Median overall survival was 4 months (0.03 – 34.88). Patients with linear focal leptomeningeal CE had a significantly better PFS (p=0.02) however no other MRI characteristic was associated with survival. Conclusions: In this retrospective cohort of patients with BC and LM, linear focal leptomeningeal CE by pre-treatment MRI was the only significant radiographic abnormality that correlated with survival. These data will be confirmed in a larger cohort of patients.