BBBD Followed By Methotrexate and Carboplatin With or Without Trastuzumab in Treating Women With Breast Cancer That Has Spread to the Brain

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed breast cancer metastatic to the central nervous system (as documented by brain biopsy, cytology \[analysis from cerebrospinal fluid\]) OR radiographic evidence of brain metastasis with a diagnosis of systemic breast cancer * Patients must have stable or no systemic disease as determined by a CT scan of the chest, abdomen, and pelvis * HER2-positive or -negative disease by fluorescent in situ hybridization (FISH) or immunohistochemistry * Patients with HER2-positive disease and signs of intracranial herniation and/or spinal block may first undergo intraarterial chemotherapy off study (with carboplatin, methotrexate, and trastuzumab \[Herceptin®\] by the same routes used on study) until radiographically shown to be safe to undergo blood brain barrier disruption, at which point they may be enrolled in the study * Hormone receptor status not specified PATIENT CHARACTERISTICS: * Female * Menopausal status not specified * ECOG performance status (PS) 0-2 OR Karnofsky PS 60-100% * Life expectancy \> 6 weeks * Hematocrit ≥ 25% * WBC ≥ 2,500/mm³ * Absolute neutrophil count ≥ 1,200/mm³ * Platelet count ≥100,000/mm³ * Creatinine clearance ≥ 50 mL/min (eligible for full-dose methotrexate) (30-49 mL/min allowed for patients receiving reduced-dose methotrexate) * Bilirubin ≤ 2.0 times upper limit of normal * LVEF normal by echocardiogram or MUGA * Adequate pulmonary and cardiac function to tolerate general anesthesia a…