RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one drug may kill more tumor cells.

PURPOSE: Phase II trial to study the effectiveness of high-dose sequential chemotherapy as adjuvant therapy in treating patients with stage II or stage III breast cancer who have four or more positive axillary lymph nodes.

OBJECTIVES: I. Evaluate the efficacy of dose intensive, sequential adjuvant chemotherapy with doxorubicin, paclitaxel, and cyclophosphamide in patients with stage II/III resected breast cancer. II. Evaluate the toxicity of this regimen in these patients.

OUTLINE: All patients receive sequential chemotherapy regimens consisting of 3 courses each of doxorubicin, paclitaxel, and cyclophosphamide on a schedule of one course every 14 days. Following completion of chemotherapy, patients who underwent breast conservation surgery receive radiotherapy. Mastectomy patients with 10 or more positive nodes or with T3-4 tumors are also eligible for delayed radiotherapy. Patients who are hormone receptor positive (or whose receptor status is unknown) are treated with oral tamoxifen for 5 years, beginning after completion of all other therapy. Patients are followed every 3 months for 2 years, every 6 months for 3 years, then yearly.

PROJECTED ACCRUAL: At total of 90 patients will be entered.

DISEASE CHARACTERISTICS: Histologically proven adenocarcinoma of the breast with involvement of 4 or more axillary nodes, including any T N1 M0 Concurrent bilateral breast cancer allowed Complete resection required Total mastectomy or breast conserving surgery Adjuvant radiotherapy planned after protocol chemotherapy Clear surgical margins Axillary dissection yielding at least 9 lymph nodes Entry required within 8 weeks of definitive surgery Hormone receptor status: Any status

PATIENT CHARACTERISTICS: Age: Over 18 Sex: Not specified Menopausal status: Not specified Performance status: Karnofsky 80%-100% ECOG 0 or 1 Hematopoietic: Absolute granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 10 g/dL Hepatic: Bilirubin no greater than 1.5 times normal AST no greater than 2 times normal Alkaline phosphatase no greater than 2 times normal Renal: Creatinine no greater than 1.8 mg/dL OR Creatinine clearance at least 60 mL/min Urinalysis normal Cardiovascular: Left ventricular ejection fraction normal on MUGA or echocardiogram No congestive heart failure requiring medical therapy No serious arrhythmia No first-, second-, or third-degree heart block Other: No abnormal CT of chest or abdomen No uncontrolled infection No serious medical condition that would prevent treatment No second malignancy except curatively treated: Nonmelanomatous skin cancer Carcinoma in situ of the cervix Not pregnant Negative pregnancy test Barrier contraception required of fertile patients before, during, and for 6 months after protocol therapy

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior systemic chemotherapy Endocrine Therapy: No concurrent hormonal therapy unless unrelated to cancer Radiotherapy: See Disease Characteristics Surgery: See Disease Characteristics Other: No concurrent medication affecting conduction unless cleared by a cardiologist, e.g.: Beta blockers Digoxin Antiarrhythmia agents Calcium channel blockers