Neoadjuvant treatment in breast cancer. Role of the pathologist

Neoadjuvant treatment is a standard practice in patients with breast cancer that allows to perform more conservative surgeries, provides additional prognostic information and is very useful for evaluating the efficacy of drugs. Pathologists are of great importance in this context. The evaluation of the tumor in diagnostic biopsy is essential for a correct selection of patients who are candidates for neoadjuvant therapy. In order to standardize the management and pathological evaluation of breast and axillary specimens that have received treatment, a homogeneous definition of complete pathological response has been established and, in the case of residual disease, its quantification using the RCB system is recommended because it is objective, reproducible and clinically useful. The sampling of these specimens and the subsequent microscopic study should be able to provide the necessary data for the correct diagnosis of the complete pathological response and to be able to quantify the residual cancer burden (RCB). (C) 2022 SESPM. Published by Elsevier Espana, S.L.U. All rights reserved.