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 as determined by physical examination and history
* No New York Heart Association class III-IV heart disease
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* No known allergy to trastuzumab (HER2-positive patients), carboplatin, methotrexate, or sodium thiosulfate
* No hepatitis B or C positivity
* No uncontrolled intercurrent illness including, but not limited to, any of the following:

  * Ongoing or active infection (e.g., HIV)
  * Symptomatic congestive heart failure
  * Unstable angina pectoris
  * Cardiac arrhythmia
  * Psychiatric illness or social situations that would limit compliance with study requirements

PRIOR CONCURRENT THERAPY:

* Prior surgery or biopsy allowed
* Prior chemotherapy and radiation therapy for metastatic breast cancer allowed
* No radiation or cytotoxic chemotherapy within the past 4 weeks (except trastuzumab or hormone therapy that has been part of the patient's ongoing treatment \[e.g., aromatase inhibitors for estrogen receptor positive patients\])
* No noncytotoxic regimens (e.g., targeted oral agents) within the past 2 weeks
* No investigational agents within the past 4 weeks
* No other concurrent anticancer agents or therapies