RATIONALE Preoperative chemotherapy enables breast-conserving surgery for some patients with breast cancer, and it might be advantageous in several other ways. For example, the response to primary treatment may be used as a prognostic marker, since it has been demonstrated to be associated with a longer disease-free survival (DFS) compared with no response. In particular the degree of response (pathological complete remission (pCR)) predicts overall outcome in terms of DFS.