Liposomal Cytarabine and High-Dose Methotrexate in Treating Patients With Central Nervous System Metastases From Breast Cancer

Inclusion Criteria: * Women who are not pregnant (contraception must be used throughout the study) * Diagnosis of breast cancer with metastases to CNS (regardless of receptor status); leptomeningeal disease must be present with/without parenchymal brain involvement * Able to provide informed consent * No prior treatment with whole brain radiotherapy (WBRT); if patient received stereotactic radiosurgery (SRS) prior to enrollment it must be well documented which lesions were treated and untreated index lesions for follow up must be identified; no treatment with SRS will be permitted while on the study; CNS disease must be documented by MRI and CSF cytology * Karnofsky Performance Status \> 60 * White blood cells (WBC) \>= 3.0 K * Absolute neutrophil count (ANC) \>= 1.5 K * Platelets (PLT) \>= 100 K * Hematocrit (HCT) \>= 30% * Glomerular filtration rate (GFR) \>= 60 mL/min * Acceptable liver function (see exclusion criteria) * Any ongoing therapy for systemic disease allows for the addition of systemic HD-MTX and IT Depocyt; in general patients receiving trastuzumab or lapatinib at the time of enrollment will be allowed to continue; bisphosphonates (i.e., zoledronic acid) and denosumab will be allowed; other non-CNS active chemotherapies might be allowed if no known interactions with study drugs are present; this must be reviewed and approved by the primary investigator on a case-by-case basis * Mini-mental state examination score of 24 or above Exclusion Criteria: * Serum b…