DISEASE CHARACTERISTICS:

• Histologically confirmed breast cancer
• Metastatic disease

• Prior treatment with taxanes in the metastatic, adjuvant, or neoadjuvant setting

  • Taxane-resistant disease allowed regardless of duration of prior therapy NOTE: Resistant disease defined as progression during or within 12 weeks after taxane therapy for metastatic disease or a disease-free interval of less than 12 months after neoadjuvant or adjuvant therapy with a taxane
  • Taxane-sensitive disease allowed if at least 4 prior courses were received NOTE: Sensitive disease defined as progression occurring more than 12 weeks after taxane therapy for metastatic disease or more than 12 months after neoadjuvant or adjuvant therapy with a taxane
• Prior treatment with anthracyclines for metastatic disease or as adjuvant treatment OR medical contraindication to treatment with anthracyclines
• At least one unidimensionally measurable lesion (phase II study)
• No CNS metastases

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age

• 18 and over

Sex

• Female

Menopausal status

• Not specified

Performance status

• Karnofsky 70-100%

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic

• Bilirubin no greater than 1.25 times upper limit of normal (ULN)
• Transaminases no greater than 2.5 times ULN (5 times ULN if liver metastases present)

Renal

• Creatinine clearance greater than 50 mL/min

Cardiovascular

• No symptomatic ventricular arrhythmias
• No clinically significant congestive heart failure
• No clinical or ECG evidence of myocardial infarction within the past 12 months
• No significant coronary artery disease

Other

• Not pregnant or nursing
• Fertile patients must use effective contraception
• No prior malignancy within the past 5 years except contralateral breast cancer, nonmelanoma skin cancer, and adequately treated carcinoma in situ of the cervix
• No known or prior sensitivity to fluoropyrimidines, including fluorouracil
• No pre-existing grade 2 or greater neurotoxicity
• No known malabsorption or upper gastrointestinal abnormalities that would affect absorption of study drug
• No psychological, familial, sociological, or geographical condition that would preclude study compliance

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent biologic therapy

Chemotherapy

• See Disease Characteristics
• No more than 2 prior chemotherapy lines for metastatic disease
• No prior capecitabine, vinca alkaloids, or continuous fluorouracil
• No other concurrent chemotherapy

Endocrine therapy

• Prior hormonal therapy allowed
• No concurrent hormonal therapy

Radiotherapy

• No concurrent radiotherapy

Surgery

• Not specified

Other

• Bisphosphonate therapy for treatment and prevention of bony metastases allowed if initiated prior to study
• No other concurrent investigational treatment
• No concurrent brivudine with capecitabine