Neoadjuvant chemotherapy with epirubicin and cyclophosphamide makes breast conserving therapy possible in patients with large tumors, which are primarily not suited for this treatment. The regression of the tumor can be followed by mammography, ultrasound and MRI. Mammography is reproducible and easily available. Tumors, which cannot be measured mammographically, usually can be followed with ultrasound. MR allows imaging of the tumor independent of structure and density of the parenchyma. In addition the measurement of functional parameters is possible. All methods are restricted in the imaging of tumor residuals after neoadjuvant chemotherapy, because imaging of small microscopic foci of invasive or even non invasive tumorresiduals is hardly possible. Of special concern are tumor specific microcalcifications, which only can be shown on mammograms, in this respect. They do not regress under chemotherapy, even if the invasive tumor regresses, and they typically hint for non invasive tumor residuals. For planning surgery the pretherapeutic tumor extent always has to be taken into account, because of the restricted ability to image small tumor residuals.