Inclusion Criteria

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
a minimum projected 5 year probability of invasive breast cancer of at least 1.66%,
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