DISEASE CHARACTERISTICS:

• Histologically confirmed primary infiltrating adenocarcinoma of the breast

  • Confirmed by core needle biopsy or incisional biopsy
  • Amplification of HER-2 by FISH OR
  • Overexpression (3+) of HER-2 by immunohistochemistry

  • Staging criteria after complete clinical and radiographic staging:

    • T3, N1, M0 OR
    • Any T, N2 or N3, M0 OR
    • T4, any N, M0, including clinical or pathological inflammatory disease OR
    • Regional stage IV disease with supraclavicular or infraclavicular lymph nodes as only site of metastasis
• Measurable or evaluable disease
• Prior ductal carcinoma in situ of the ipsilateral breast allowed if treated with excision only without mastectomy or radiation
• Metaplastic carcinoma allowed
• Synchronous bilateral primary disease allowed (provided at least 1 cancer meets staging criteria)
• No dermal lymphatic involvement with clinical inflammatory changes

• Hormone receptor status:

  • Estrogen receptor positive or negative
  • Progesterone receptor positive or negative

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Sex:

• Female

Menopausal status:

• Not specified

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• Granulocyte count at least 1,000/mm3
• Platelet count at least 100,000/mm3

Hepatic:

• Bilirubin no greater than upper limit of normal (ULN)
• AST no greater than 2 times ULN

Renal:

• Creatinine no greater than 1.5 times ULN

Cardiovascular:

• LVEF normal by MUGA
• No uncontrolled or severe cardiovascular disease (e.g., myocardial infarction within the past 6 months, congestive heart failure treated with medications, or uncontrolled hypertension)

Other:

• No other currently active malignancy except nonmelanoma skin cancer
• Not pregnant or nursing
• Fertile patients must use effective contraception
• Patients taking tamoxifen must use effective nonhormonal contraception during and for 2 months after study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior chemotherapy
• No other concurrent chemotherapy

Endocrine therapy:

• No more than 4 weeks of prior tamoxifen for disease
• Prior tamoxifen or raloxifene for longer than 4 weeks as chemoprevention allowed
• No concurrent tamoxifen or raloxifene
• No other concurrent hormonal therapy except for steroids for adrenal failure, hormones for non-disease-related conditions (e.g., insulin for diabetes), or intermittent dexamethasone as an antiemetic

Radiotherapy:

• See Disease Characteristics
• No prior radiotherapy for index malignancy
• No prior radiotherapy to the ipsilateral breast, regional nodes, mediastinum, or heart
• Prior radiotherapy to the contralateral breast for ductal carcinoma in situ or early stage invasive breast cancer allowed provided earlier radiotherapy does not preclude optimal delivery of study radiotherapy and criterion of low risk for metastasis from first malignancy is met

Surgery:

• See Disease Characteristics
• No prior sentinel lymph node biopsy