1. Patients must be premenopausal women with a histologically confirmed diagnosis of operable Stage I, II, or IIIA invasive breast cancer. Patients who have completed surgery must have pathologic Stage I, II, or IIIa disease. Patients to be treated in the preoperative setting may be staged clinically but must have operable disease. For the purposes of this study, premenopausal is defined as the presence of cyclic menstrual bleeding within 6 weeks prior to randomization or documentation of FSH and estradiol levels in the premenopausal range.