Inclusion Criteria

DISEASE CHARACTERISTICS:

- Women at high risk for breast cancer, defined by at least 1 of the following
criteria:

- Projected 5-year probability of invasive breast cancer at least 1.66%, as
determined by the Breast Cancer Risk Assessment Tool

- Prior node-negative breast cancer

- Prior biopsy indicating atypical lobular or ductal hyperplasia or carcinoma in
situ

- Age 60 and over

- Non-smoker confirmed by urine cotinine test

- No concurrent breast cancer

- Hormone receptor status:

- Not specified

PATIENT CHARACTERISTICS:

Age:

- 18 to 70

Sex:

- Female

Menopausal status:

- Premenopausal (regular menstrual cycles of 24-36 days within the past 6 months) OR

- Postmenopausal (no menstrual cycle for at least 6 months)

Performance status:

- Not specified

Life expectancy:

- At least 1 year

Hematopoietic:

- Absolute granulocyte count greater than 1,500/mm^3

- Hemoglobin greater than 10 g/dL

Hepatic:

- Bilirubin less than 1.8 mg/dL

- AST and ALT less than 110 U/L

- Alkaline phosphatase less than 300 U/L

- Albumin greater than 3 g/dL

Renal:

- Creatinine less than 2.0 mg/dL

Cardiovascular:

- No acute or unstable cardiovascular condition based on electrocardiogram

Other:

- Mild seasonal allergies allowed

- No serious or life-threatening drug allergies

- No other serious intolerances or allergies

- No more than 20% above or below ideal body weight

- No acute or unstable medical condition by physical examination or laboratory tests

- No chronic headaches, dysphoria, fatigue, dizziness, blurred vision, insomnia,
rhinorrhea, nausea, vomiting, abdominal pain, diarrhea, constipation, or similar
conditions

- No serious illness requiring chronic drug therapy

- No active malignancy

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective barrier contraception 1 month before, during, and
for 1 month after study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- No prior chemotherapy

Endocrine therapy:

- At least 2 months since prior hormonal therapy as contraception or hormone
replacement therapy (HRT)

- No concurrent sex hormones as contraception for premenopausal women

- No concurrent HRT for postmenopausal women

Radiotherapy:

- Not specified

Surgery:

- Not specified

Other:

- At least 6 months since prior investigational drugs

- At least 1 month since prior weekly consumption of more than 3 medium servings (half
cup each) of cruciferous vegetables

- No concurrent vegetarian diet or weekly consumption of more than 3 medium servings
(half cup each) of cruciferous vegetables

- No continuous supplement intake

- No recent change in medications or dosage of medications