DISEASE CHARACTERISTICS:

• High genetic risk of developing breast cancer defined as one or more of the following:

  • BRCA1 or BRCA2 germ-line mutation
  • First-degree relative of known BRCA1 or BRCA2 mutation carrier
  • Family with 4 or more relatives diagnosed with female or male breast cancer or ovarian cancer before the age of 60
  • Two first-degree relatives diagnosed with breast cancer before the age of 40
  • p53 germ-line mutation (classical Li-Fraumeni syndrome (LFS) only)
  • First-degree relative of a carrier in a family with classical LFS
  • Risk equivalent to any of the above confirmed by clinical geneticist

• No evidence of breast cancer by mammography

  • Suspicious lesions must be confirmed as non-malignant
• No prior breast cancer
• No prior prophylactic mastectomy
• No plan for alternative prevention measures within the next 12 months

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age:

• 30 to 45

Sex:

• Female

Menopausal status:

• Premenopausal (follicle-stimulating hormone in premenopausal range if not menstruating)

Performance status:

• Not specified

Life expectancy:

• More than 10 years (excluding breast cancer risk)

Hematopoietic:

• Not specified

Hepatic:

• Adequate liver function

Renal:

• Adequate renal function

Cardiovascular:

• No prior deep vein thrombosis

Pulmonary:

• No prior pulmonary embolism

Other:

• Not pregnant
• Fertile patients must use effective nonhormonal contraception
• No psychological disorder that would preclude study compliance
• No prior malignancy within the past 5 years except curatively treated nonmelanoma skin cancer or cervical cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Not specified

Endocrine therapy:

• No concurrent hormonal therapy (e.g., oral contraception or hormone replacement therapy)

Radiotherapy:

• Not specified

Surgery:

• See Disease Characteristics

Other:

• At least 30 days or 5 half-lives since prior investigational drugs
• No concurrent anticoagulants