Inclusion Criteria:

1. Signed inform consent.
2. Patients must be age 18 or older.
3. Histological or cytologically confirmed invasive breast cancer, with Stage IV disease.
4. Patient must have evidence of radiographically measurable CNS metastases (greater than or equal to 10mm on T1-weighted gadolinium-enhanced MRI) within 2 weeks prior to starting treatment. Patients without known extra-CNS disease are eligible.
5. All patients must have metastases in the brain. Patients with concurrent leptomeningeal carcinomatosis are eligible for the study. Local radiation to sites of meningeal involvement in the spine is allowed.
6. No prior whole brain radiation.
7. Patients who had previous stereotactic brain irradiation are eligible, provided they have new measurable brain lesions (which has not been radiated previously) and will receive WBRT at 30Gy over 10 fractions.
8. Patients may undergo surgical resection of CNS metastases if clinically indicated, but must have remaining measurable disease in the brain after surgery.
9. No prior treatment with capecitabine in the adjuvant or metastatic settings. Patients may have completed 5-fluorouracil based treatment in the adjuvant setting or metastatic setting more than one year prior.
10. Patients who had previous trastuzumab therapy will be eligible but treatment will be discontinued prior to enrollment.
11. Cardiac ejection fraction within institutional range of normal as measure by echocardiogram or MUGA scans at baseline.

12. Hematological adequacy as indicated by:

    • ANC greater than or equal to 1000mg/mm3
    • Hemoglobin greater than or equal to 9gm/dL
    • Platelets greater than or equal to 50,000/mm3.

13. Hepatic adequacy as indicated by:

    • Bilirubin less than or equal to 2.0 times upper limit of normal
    • AST and ALT less than or equal to 5 times upper limit of normal.

14. Renal adequacy as indicated by:

    • Creatinine less than or equal to 1.5 times upper limit of normal
15. Patients must have recovered from toxicity of prior chemotherapy with laboratory values as specified above. Concurrent treatment with bisphosphonates is permitted.
16. Performance status of ECOG 0-1.
17. Life expectancy of at least 12 weeks.
18. At least 3 weeks since major surgical procedures.
19. Able to swallow and retain oral medication.

Exclusion Criteria:

1. Patients who are pregnant or breast feeding.
2. Known allergy to capecitabine or 5-fluorouracil.
3. Known to have dihydropyrimidine dehydrogenase (DPD) deficiency.
4. Patients who have leptomeningeal carcinomatosis as the only site of CNS metastases.
5. Patients taking concomitant medications which are CYP3A4 inhibitors or inducers.
6. Patients who will receive intrathecal chemotherapy for leptomeningeal disease.
7. Patients with psychiatric or addictive disorders that would adversely effect compliance with oral medication.
8. Life expectancy less than 3 months.
9. Patients with symptomatic lymphangitic spread to lung.
10. Malabsorption syndrome, disease significantly affecting gastrointestinal function, or resection of the stomach or small bowel.
11. History of immediate or delayed hypersensitivity reaction to gadolinium contrast agents, or other contraindication or gadolinium contrast.
12. Other known contraindication to MRI, such as a cardiac pacemaker, implanted cardiac defibrillator, brain aneurysm clips, cochlear implant, ocular foreign body, or shrapnel,

13. Vascular disease within 12 months prior to enrollment, defined as one or more of the following:

    • history of documented myocardial infarction (including severe/unstable angina)
    • Coronary/peripheral artery bypass graft
    • Symptomatic heart failure (CHF)
    • Cerebrovascular accident or transient ischemic attack
    • Pulmonary embolism,
14. Uncontrolled infection
15. History of other malignancy, except for curatively treated basal cell carcinoma or squamous cell carcinoma of the skin, or carcinoma in situ of the cervix. Subjects with other malignancies who have been disease-free for at least 5 years are eligible