Combination Chemotherapy in Treating Patients With Early Stage Breast Cancer That Has Been Removed By Surgery

RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving more than one drug (combination chemotherapy) may kill more tumor cells. Giving combination chemotherapy after surgery may kill any remaining tumor cells. It is not yet known which combination chemotherapy regimen is more effective in treating early stage breast cancer that has been removed by surgery. PURPOSE: This randomized phase III trial is studying four different combination chemotherapy regimens to compare how well they work in treating patients with early stage breast cancer that has been removed by surgery.