Neoadjuvant therapy of breast cancer. Indications and evaluation of response

Over the last two decades neoadjuvant system therapies have been implemented for operable (early) breast cancer within the framework of large randomized and prospective studies. In comparison to the established adjuvant therapies, neoadjuvant therapy additionally offers direct measurement of tumor response and therefore represents a so-called in vivo chemosensitivity test. Research of literature and clinical trials. In several studies by the Working Group Gynecological Oncology (AGO-breast) and the German Breast Group (GBG) as well as in some international studies, the significance of the response and in particular pathological complete remission (pCR) was investigated. The pCR showed good correlation with the prognosis and can therefore be used as a surrogate criterion to compare various forms of therapy with each other or to implement new forms of therapy, even before the necessary follow-up observation period of 5 or 10 years has been completed. This is coupled with the treatment concept to incorporate new target substances in order to achieve a better individualization and better results. This review article reports on the possibilities to improve survival by increasing the pCR in patients with early breast cancer. The pCR is less predictive as a surrogate criterion for luminal tumors and in this case translational biomarker studies will identify patient collectives which will especially benefit from a defined therapy or those which do not actually need such therapy. Furthermore, the significance of residual tumor tissue for the further prognosis of patients and the possibility of individualized neoadjuvant chemotherapy derived from previous responses will be discussed.