DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed early adenocarcinoma of the breast

  • Completely excised by surgery with curative intent (R0)

    • Any N OR
    • Any primary tumor greater than 3 cm OR
    • Any primary tumor grade III and greater than 1 cm
  • M0
• No positive supraclavicular nodes

• Hormone receptor status:

  • Estrogen and/or progesterone receptor positive

PATIENT CHARACTERISTICS:

Age:

• Any age
• See Menopausal status

Sex:

• Female

Menopausal status:

• Postmenopausal

  • Any age with bilateral oophorectomy or amenorrhea for at least 5 years OR

  • Age 50 or over:

    • Natural amenorrhea for at least 1 year OR
    • Chemotherapy-induced amenorrhea for at least 2 years OR
    • Radiation-induced amenorrhea (at least 3 months since prior radiotherapy) OR

  • Under age 50:

    • If amenorrheic for less than 5 years (any cause) or prior hysterectomy without bilateral surgical oophorectomy, follicle-stimulating hormone must be assayed to confirm postmenopausal status

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• Platelet count greater than 100,000/mm3
• WBC greater than 3,000/mm3

Hepatic:

• SGOT or SGPT less than 2.5 times upper limit of normal (ULN)

Renal:

• Creatinine less than 1.5 times ULN

Cardiovascular:

• No uncontrolled cardiac disease
• No unstable angina
• No congestive heart failure or arrhythmia requiring medical therapy
• No myocardial infarction within the past 3 months

Other:

• No severe osteoporosis
• No other malignancies within the past 5 years except adequately treated carcinoma in situ of the cervix or basal cell skin cancer
• No other serious concurrent disease that would preclude study
• No psychiatric disorders that would preclude study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior neoadjuvant chemotherapy
• No more than 10 weeks since completion of prior adjuvant chemotherapy

Endocrine therapy:

• No prior adjuvant hormonal therapy for breast cancer
• No prior neoadjuvant hormonal therapy (prior to surgery) for duration of more than 4 weeks
• At least 4 weeks since prior hormone replacement therapy

Radiotherapy:

• Not specified

Surgery:

• See Disease Characteristics
• No more than 10 weeks since completion of curative surgery

Other:

• No other concurrent investigational agents or participation in another clinical study (except adjuvant cytotoxic chemotherapy studies)
• Concurrent bisphosphonates allowed