Indole-3-Carbinol in Preventing Breast Cancer in Nonsmoking Women Who Are at High Risk For Breast Cancer

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 * Aspartate aminotransferase (AST) and Alanine transaminase (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