CLINICAL MORPHOLOGICAL CHARACTERISTICS OF THE RESULTS OF NEOADJUVANT CHEMOTHERAPY IN BREAST CANCER

Background. Tumor response to neoadjuvantchemyotherapy (NACT) in breast cancer is determined using clinical and pathological criteria. Objective. To evaluate the effectiveness of NACT in breast cancer on the basis of clinical and morphological parameters and to analyze the dynamics of changes in the molecular and genetic parameters of the tumor before and after induction chemotherapy. Materials and methods. We investigated biomaterials samples of breast tumors collected prior to NACT initiation and after its completion. We evaluated immunohistochemical status of the tumor and response to NACT using the criteria RECIST 1.1 and pathological classification of Lavnikova-Miller-Payne. Results. Complete clinical regression of tumors was observed in 31,6% cases, complete pathologic response – 15,8%. Changes in the immunophenotype of the tumor after NAСT occurred in different directions. Conclusions. Pathomorphological assessment of residual tumor is an important component in the initial evaluation of NACT regimens efficacy. A decrease in Ki-67 indicates a positive tumor response to NACT.