Combination Chemotherapy and Filgrastim Before Surgery in Treating Patients With HER2-Positive Breast Cancer That Can Be Removed By Surgery

PRIMARY OBJECTIVES: I. To assess the pathologic response rate in patients with operable breast cancer treated with a two part, neoadjuvant regimen consisting of weekly doxorubicin (doxorubicin hydrochloride) and daily oral cyclophosphamide given with G-CSF (filgrastim) support for 12 weeks followed weekly paclitaxel for 12 weeks. SECONDARY OBJECTIVES: I. To assess the clinical response rate in patients with surgically resectable breast cancer treated with weekly doxorubicin and daily oral cyclophosphamide given with G-CSF support for 12 weeks. II. To assess the clinical response rate in patients with surgically resectable breast cancer treated with weekly paclitaxel for 12 weeks. III. To assess the relapse rate, overall and disease-free survival in patients with operable breast cancer treated with neoadjuvant chemotherapy consisting of weekly doxorubicin and daily oral cyclophosphamide given with G-CSF support for 12 weeks followed weekly paclitaxel for 12 weeks and adjuvant chemotherapy with Xeloda (capecitabine), Methotrexate and Navelbine (vinorelbine tartrate) (XMN). IV. To assess the toxicity associated with these regimens. V. To assess whether the phenotype of breast cancer changes with treatment. VI. To assess whether phenotypic changes in breast tumors predict outcome. OUTLINE: PART I: Patients receive doxorubicin hydrochloride intravenously (IV) on day 1 of each week, cyclophosphamide orally (PO) once daily (QD), and filgrastim subcutaneously (SC) QD on days 2-7 of each week. Treatment continues for 12 weeks in the absence of disease progression or unacceptable toxicity. PART II: Patients\* receive paclitaxel IV over 1 hour on day 1 of each week. Treatment continues for 12 weeks in the absence of disease progression or unacceptable toxicity. Patients then undergo definitive surgical resection by partial mastectomy (lumpectomy) or mastectomy after completion of neoadjuvant chemotherapy. PART III: Patients\*\* unable to achieve complete pathologic response (pCR) or disease that has been down-staged to =\< 1 cm with no positive nodes following surgery receive capecitabine PO twice daily (BID) on days 1-14, methotrexate IV on days 1, 8 and 15, and vinorelbine tartrate IV over 6-10 minutes on days 1, 8, and 15. Treatment repeats every 3 weeks for 4 courses in the absence of disease progression or unacceptable toxicity. NOTE: \*Patients with HER2/neu-positive disease also receive trastuzumab IV over 30-90 minutes once weekly or every 3 weeks for 1 year beginning in Part II. NOTE: \*\*Patients with hormone receptor-positive disease also receive tamoxifen PO QD for 5 years (premenopausal) OR letozole PO QD or tamoxifen PO QD for 5 years (postmenopausal) beginning in Part III. After completion of study treatment, patients are followed up every 3 months for 3 years, every 6 months for 2 years, and then annually thereafter.