Combination Chemotherapy in Treating Women Who Have Undergone Surgery for Node-Positive Breast Cancer

OBJECTIVES: Primary * Compare disease-free survival in women with node-positive breast cancer treated with 3 different adjuvant chemotherapy regimens comprising dose-dense doxorubicin, cyclophosphamide, paclitaxel, and gemcitabine vs docetaxel, doxorubicin, and cyclophosphamide vs dose-dense doxorubicin, cyclophosphamide, and paclitaxel. Secondary * Compare overall survival, recurrence-free interval, and distant recurrence-free interval, in patients treated with these regimens. * Compare the toxic effects of these regimens in these patients. OUTLINE: This is a randomized, multicenter study. Patients are stratified according to number of positive lymph nodes (1-3 vs 4-9 vs ≥ 10), hormone receptor status (estrogen receptor \[ER\]- and progesterone receptor \[PgR\]- negative vs ER- and/or PgR-positive), type of prior surgery and planned radiotherapy (lumpectomy and local radiotherapy \[RT\] without regional RT vs lumpectomy and local RT with regional RT vs mastectomy without RT vs mastectomy with local or regional RT). Patients are randomized to 1 of 3 treatment arms. * Group 1: Patients receive doxorubicin IV over 15 minutes, cyclophosphamide IV over 30 minutes, and docetaxel IV over 1 hour on day 1. Treatment repeats every 21 days for 6 courses. * Group 2: Patients receive AC chemotherapy comprising doxorubicin IV over 15 minutes and cyclophosphamide IV over 30 minutes on day 1. Treatment repeats every 14 days for 4 courses. Beginning 14 days after the last dose of AC, patients receive paclitaxel IV over 3 hours on day 1. Treatment repeats every 14 days for 4 courses. * Group 3: Patients receive AC chemotherapy as in Group 2. Beginning 14 days after the last dose of AC, patients receive paclitaxel as in Group 2 and gemcitabine IV over 30-60 minutes on day 1. Treatment repeats every 14 days for 4 courses. In all arms, treatment continues in the absence of disease progression or unacceptable toxicity. Beginning 3-12 weeks after the last dose of chemotherapy, patients with ER-positive and/or PgR-positive tumors receive hormonal therapy. Beginning no sooner than 3 weeks after the last dose of chemotherapy, patients treated with lumpectomy undergo whole-breast radiotherapy. Patients treated with mastectomy may undergo chest wall and/or regional nodal radiotherapy. Patients are followed every 6 months for 5 years and then annually thereafter. PROJECTED ACCRUAL: A total of 4,800 patients will be accrued for this study within 4 years.