DISEASE CHARACTERISTICS:

• Histologically confirmed invasive adenocarcinoma of the breast

  • Primary tumor T1-3 by clinical and pathologic evaluation

    • No T4 disease
  • No pure tubular or mucinous adenocarcinoma
• No bilateral malignancy, including ductal carcinoma in situ (DCIS) or a mass or mammographic abnormality in the opposite breast unless it is proven benign by biopsy

• No diffuse tumors by mammography that would not be amenable to lumpectomy

  • Eligible if undergone mastectomy

• All lymph nodes must be _ pN_0 by 1 of the following axillary nodal staging procedures:

  • Sentinel node (SN) biopsy alone
  • SN biopsy followed by axillary sampling or complete dissection
  • Axillary node dissection* to obtain lymph nodes for pathologic evaluation NOTE: *Required if patient has palpable nodes in the ipsilateral or contralateral axilla or palpable supraclavicular or infraclavicular nodes

• Must have undergone either a lumpectomy or total mastectomy within the past 84 days

  • If lumpectomy has been performed, margins must be histologically confirmed free of invasive tumor or DCIS

    • If tumor is found to be present in margins, further surgical resection or total mastectomy must be performed until clear margins are achieved

      • Margins that are positive for lobular carcinoma in situ (LCIS) do not require further resection

    • No other clinically dominant mass or mammographically suspicious abnormality within the ipsilateral breast remnant

      • Must be biopsied and demonstrated to be histologically benign OR surgically removed with clear margins

• No prior breast cancer, including DCIS

  • Prior LCIS allowed

• No clinical or radiologic evidence of metastatic disease

  • Patients with skeletal pain must be free of metastases by bone scan or roentgenological examination

    • Suspicious findings must be confirmed as benign by x-ray, MRI, or biopsy

• Hormone receptor status:

  • Any status is eligible, but status must be determined before randomization

PATIENT CHARACTERISTICS:

Age

• 18 and over

Sex

• Female

Menopausal status

• Postmenopausal, defined by 1 of the following:

  • Prior documented bilateral oophorectomy
  • No spontaneous menstrual bleeding within the past 12 months
  • 55 years of age or older with a prior hysterectomy
  • 54 years of age or younger with a prior hysterectomy without oophorectomy (or in whom the status of ovaries is unknown) with a documented follicle-stimulating hormone level demonstrating confirmatory elevation in the postmenopausal range OR
• Premenopausal

Performance status

• Not specified

Life expectancy

• At least 10 years, excluding the diagnosis of breast cancer

Hematopoietic

• Absolute granulocyte count ≥ 1,500/mm^3 (1,200/mm^3 if due to ethnic or racial variance)
• Platelet count ≥ 100,000/mm^3
• No significant underlying hematologic disorders causing platelet count to be > upper limit of normal (ULN)

Hepatic

• Bilirubin normal (≤ 1.5 times ULN if due to Gilbert's syndrome)
• Alkaline phosphatase < 2.5 times ULN
• AST ≤ 1.5 times ULN

Renal

• Creatinine normal

Cardiovascular

• LVEF normal by MUGA or echocardiogram
• No myocardial infarction
• No angina pectoris requiring anti-anginal medication
• No history of congestive heart failure
• No serious cardiac arrhythmia requiring medication
• No severe conduction abnormality
• No valvular disease with documented cardiac function compromise
• No poorly controlled hypertension (i.e., diastolic > 100 mm Hg)
• No other cardiac disease that would preclude anthracycline therapy

Other

• No other malignancy within the past 5 years except adequately treated carcinoma in situ of the cervix, melanoma in situ, or basal cell or squamous cell skin cancer
• No non-malignant systemic disease that would preclude study participation or prolonged follow-up
• No psychiatric or addictive disorder or other condition that would preclude study participation
• Not pregnant or nursing
• Fertile patients must use effective barrier contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No prior biologic therapy for breast cancer

Chemotherapy

• No prior chemotherapy for breast cancer
• No prior anthracyclines

Endocrine therapy

• Prior hormonal therapy for breast cancer allowed provided therapy was ≤ 28 days in duration

• No concurrent oral or parenteral sex hormones (e.g., hormone replacement therapy)

  • Concurrent hormonal therapy for the management of vaginal or urinary symptoms allowed as follows:

    • Low-dose estrogen in the form of a vaginal cream (≤ 0.3 mg or 1/8 of an applicator 3 times per week)
    • Conjugated estrogen ring (e.g., Estring®)
    • Vagifem®
• No concurrent luteinizing hormone releasing-hormone agonists or antagonists (e.g., goserelin)
• No concurrent selective estrogen-receptor modulators (e.g., raloxifene) for osteoporosis or breast cancer prevention

Radiotherapy

• No prior radiotherapy for breast cancer
• No concurrent regional nodal radiotherapy
• No concurrent partial breast radiotherapy except for patients treated in the partial breast irradiation group of protocol NSABP-B-39

Surgery

• See Disease Characteristics

Other

• No other concurrent investigational agents