Trastuzumab and External Beam Radiation Therapy in Treating Women With Stage III or Stage IV Breast Cancer

You may be eligible if

• DISEASE CHARACTERISTICS:
• Histologically confirmed\* invasive primary carcinoma of the breast by fine-needle aspiration, core needle biopsy, or incisional biopsy
• Excisional biopsy is not allowed
• Stage III or IV disease (clinical and radiographic staging), including any of the following:
• * Any T with N2 disease (metastasis to ipsilateral axillary lymph nodes fixed to one another or other structures) or N3 disease (metastasis to ipsilateral internal mammary lymph nodes)
• * T4, any N disease
• * Inflammatory disease
• * Supraclavicular and/or infraclavicular adenopathy
• * Distant metastasis with measurable disease in the breast or lymph nodes
• HER2-overexpressing tumor
• Measurable or evaluable disease
• Residual locoregional disease after completion of neoadjuvant chemotherapy OR locoregional recurrent disease
• Synchronous bilateral primary cancers allowed provided the more serious of the two cancers meets staging criteria
• Hormone receptor status not specified
• PATIENT CHARACTERISTICS:
• Menopausal status not specified
• WBC \> 2,000/mm\^3
• Platelet count \> 50,000/mm\^3
• Hemoglobin \> 11 g/dL
• Negative pregnancy test
• Fertile patients must use effective contraception
• Radionucleotide ventriculography/LVEF normal OR ≤ 10% asymptomatic decline from baseline after completion of neoadjuvant chemotherapy
• PRIOR CONCURRENT THERAPY:
• See Disease Characteristics
• No prior radiotherapy to the breast or regional lymph nodes
• Concurrent participation in neoadjuvant chemotherapy clinical trials allowed