PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy Endocrine therapy: No prior hormonal therapy (except for up to 14 days of tamoxifen stopped prior to registration) Prior estrogen- and/or progesterone-containing hormone preparations for nononcologic therapy allowed, but must be discontinued prior to registration Postmenopausal estrogen therapy should be discontinued in all patients at the time of diagnosis of breast cancer Radiotherapy: Postoperative chest wall and/or regional lymph node irradiation allowed for mastectomy patients (at discretion of the physician) either prior to registration or on protocol for any of the following: Tumor greater than 5 cm in diameter 4 or more positive nodes Extranodal extension of tumor into the axillary fat No radiotherapy for any other reason in mastectomy patients Postoperative radiotherapy either prior to registration, during tamoxifen, or after completion of chemotherapy required for lumpectomy patients Radiotherapy must be completed (if it is to be given before chemotherapy) prior to registration No immediate radiotherapy after randomization to chemotherapy Surgery: Radical, modified radical, or breast-sparing surgical procedure with at least a level I and II axillary dissection and analysis of at least 6 nodes required within 12 weeks prior to registration Lumpectomy must include: Total excisional biopsy with rim of normal breast tissue Microscopically negative margins Level I and II axillary dissection Tumor no more than 5 cm in greatest diameter Clinical and mammographic examination demonstrating absence of multicentric lesions Type of surgery, number of nodes examined, number of positive nodes, and size of the primary tumor (size of the largest tumor if more than 1 mass) must be recorded