Résumé : Adjuvant therapy for breast cancer is an effective mean to reduce the likelihood of recurrence and to increase overall survival, as shown by the Early Breast cancer Trialists'Group Overview. Although these benefits are clearly significant, they represent a modest improvement in the care of breast cancer. The role of pre-operative chemotherapy remains to be defined in early stage breast cancer. Otherwise, pre-operative chemotherapy has become 'standard of care' in locally advanced and inflammatory breast cancer. There are still several questions to be answered in the field of adjuvant and pre-operative chemotherapy. Prospective randomized clinical studies are the only way to obtain further therapeutic progress for this highly lethal disease.