Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed metastatic adenocarcinoma of the breast

- Measurable disease outside previously irradiated area or occurred/progressed after
completion of radiotherapy

- Must have received 1 or 2 prior chemotherapy regimens for metastatic disease

- More than 3 prior regimens allowed

- No active brain metastases or meningeal breast cancer involvement

PATIENT CHARACTERISTICS:

Sex:

- Male or female

Performance status:

- SWOG 0-2

Hematopoietic:

- WBC at least 3,000/mm^3

- Platelet count at least 100,000/mm^3

- Absolute neutrophil count at least 1,500/mm^3

Hepatic:

- Bilirubin no greater than 1.5 times upper limit of normal (ULN)

- SGOT or SGPT no greater than 3 times ULN (5 times ULN for liver metastases)

Renal:

- Creatinine no greater than 1.5 mg/dL OR

- Creatinine clearance at least 60 mL/min

Cardiovascular:

- No history of myocardial infarction or unstable angina within the past 6 months

- No uncontrolled congestive heart failure

Other:

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- Prior diagnosis of cancer allowed (must be off cancer therapy and have no evidence of
disease)

- No history of retinopathy and/or macular degeneration

PRIOR CONCURRENT THERAPY:

Chemotherapy:

- No prior irofulven