DISEASE CHARACTERISTICS:

• Postmenopausal women at increased risk for developing invasive breast cancer, who meet one of the following criteria:

  • At least 12 months since spontaneous menstrual bleeding
  • Prior documented hysterectomy and bilateral salpingo-oophorectomy
  • At least 55 years of age with prior hysterectomy with or without oophorectomy
  • Age 35 to 54 with a prior hysterectomy without oophorectomy OR with a status of ovaries unknown with documented follicle-stimulating hormone level demonstrating elevation in postmenopausal range
• Histologically confirmed lobular carcinoma in situ treated by local excision only OR at least 1.66% probability of invasive breast cancer within 5 years using Breast Cancer Risk Assessment Profile
• No clinical evidence of malignancy on physical exam within the past 180 days
• No evidence of suspicious or malignant disease on bilateral mammogram within the past year
• No bilateral or unilateral prophylactic mastectomy
• No prior invasive breast cancer or intraductal carcinoma in situ

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age:

• 35 and over

Sex:

• Female

Menopausal status:

• See Disease Characteristics

Performance status:

• No restricted normal activity for a significant portion of each day

Life expectancy:

• At least 10 years

Hematopoietic:

• Granulocyte count at least 1,500/mm^3
• Complete blood count and differential normal
• Platelet count normal

Hepatic:

• SGOT or SGPT normal
• Bilirubin normal
• Alkaline phosphatase normal

Renal:

• Creatinine normal

Cardiovascular:

• No cerebral vascular accident, transient ischemic attack, atrial fibrillation, or uncontrolled hypertension
• No deep vein thrombosis

Pulmonary:

• No pulmonary embolus

Other:

• No other prior malignancy within the past 5 years except basal cell or squamous cell skin cancer or carcinoma in situ of the cervix
• No concurrent nonmalignant disease that would preclude administration of tamoxifen or raloxifene
• No clinical depression, psychiatric condition, or addictive disorder
• No uncontrolled diabetes

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Not specified

Endocrine therapy:

• At least 3 months since prior estrogen or progesterone replacement therapy, oral contraceptives, androgens, luteinizing hormone-releasing hormone analogs, prolactin inhibitors, or antiandrogens
• At least 3 months since prior tamoxifen, raloxifene, or other selective estrogen-receptor modulators of less than 3 months duration
• Concurrent Estring allowed

Radiotherapy:

• No prior breast radiotherapy

Surgery:

• See Disease Characteristics

Other:

• No prior systemic adjuvant therapy for breast cancer

• No other participation in a cancer prevention or osteoporosis prevention study involving pharmacologic intervention(s)

  • NSABP-P-1 patients who received placebo are eligible
• No concurrent warfarin or cholestyramine
• Concurrent calcitonin or nonhormonal medication (e.g., cholecalciferol, fluoride, or bisphosphonates) allowed