State of the art of neoadjuvant chemotherapy in breast cancer: rationale, results and recent developments

Aims, results, advantages and possible disadvantages of preoperative chemotherapy (pCHT) for breast cancer are discussed in this review. Established chemotherapeutic regimens are described with respect to new drugs that are added to combinations now and in the future. Illustrating the potential of new components, trastuzumab and cytotoxic chemotherapy, were combined in neoadjuvant trials for the first time. This approach yielded impressing and unprecedented high pathological response rates. An overview regarding current neoadjuvant cytostatic and immunotherapy trials is given. Established prognostic factors like axillary lymph-nodal status are altered during pCHT, which causes the need for new prognostic markers. The consequences of these changes for clinical decision making are demonstrated. It seems possible that the advances of gene array and protein expression profile technologies will lead to improved prognostic and predictive statements. Tumor tissue can be analyzed before during and after treatment in this regard recent studies investigating the response to specific, chemotherapeutics in correlation to molecular markers are reviewed. These approaches might enable us to identify chemoresistance of specific tumors. Furthermore pCHT allows testing of chemosensitivity in vivo in an early stage, which might lead to a more individualized cancer therapy. We discuss radiotherapy after neoadjuvant therapy and the risk of local relapse after breast conserving surgery, which was made feasible by pCHT. It is shown how the evaluation of efficacy of new cancer drugs, using the neoadjuvant situation, can be done more rapidly than in the metastatic and adjuvant setting.