Women meeting the following criteria will be eligible for the study: operable breast cancer (T³3cm N0-2 M0), histologically confirmed diagnosis by core-cut needle or incisional biopsy, and measurable disease by mammography or sonography or breast MRI (best appropriate method has to chosen by investigator). After the patients have given written informed consent, they will be randomised to the study treatments. All patients are scheduled to receive 4 cycles of combination chemotherapy consisting of doxorubicin 50 mg/m² (15-min i.v. infusion) and docetaxel 75 mg/m² (1-h i.v. infusion). The patients allocated to group I additionally receive oral doses of tamoxifen 30 mg once daily, starting on the first day of chemotherapy, while chemotherapy alone is administered to patients of group II. Cycles should be repeated every 14 days, followed by surgery 8 weeks after initiation of the trial. Surgery consists of removal of the remaining tumour (breastconserving resection or mastectomy) and axillary dissection. Patients with no response or even progression of the primary tumour can be treated to the discretion of the investigator but should be followed up according to protocol. If a partial or complete tumour response has been achieved, radiotherapy is given to the remaining breast in patients undergoing breast conserving therapy, and tamoxifen treatment is continued for a further 5 years.