DISEASE CHARACTERISTICS: Microscopically confirmed metastatic breast cancer Must be refractory or have recurred after at least 1 systemic chemotherapy regimen Estrogen receptor positive tumors must have failed or recurred after hormonal therapy At least 1 site of measurable disease required Previously radiated lesions are not considered measurable unless there is evidence of disease progression after completion of radiation therapy No known brain metastases Hormone receptor status: Unspecified

PATIENT CHARACTERISTICS: Age: 18 and over Menopausal status: Not specified Performance status: Zubrod 0-2 Life expectancy: At least 12 weeks Hematopoietic: WBC at least 4000/mm3 Platelet count at least 100,000/mm3 Absolute neutrophil count at least 1500/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL SGOT no greater than 2 times normal Renal: Creatinine no greater than 1.5 mg/dL BUN no greater than 30 mg/dL Other: Effective birth control must be used by fertile patients (barrier method preferred) Not pregnant or nursing

PRIOR CONCURRENT THERAPY: Recovered from toxic effects of prior treatment Biologic therapy: No immunologic therapy within the past 2 weeks Chemotherapy: No chemotherapy within the past 4 weeks (6 weeks for mitomycin or nitrosoureas) See Disease Characteristics Endocrine therapy: No hormonal therapy within the past 2 weeks See Disease Characteristics Radiotherapy: No radiotherapy within the past 4 weeks See Disease Characteristics Surgery: Not specified Other: No concurrent cholesterol lowering agents, supplemental vitamins, or other antioxidants