Progress in evaluation of pathologic response to neoadjuvant chemotherapy of breast cancer

Neoadjuvant chemotherapy is provided to patients with locally advanced breast cancer. Its main objective is to bring about a complete pathologic response which is correlated with long term patient survival, a clinical end point of preoperative chemotherapy. Besides, it may downsize the tumor, enabling breast conserving or limited mastectomy. Preoperative chemotherapy also provides the opportunity of assessing the chemosensitivity of the tumor in vivo so that postoperative chemotherapy is tailored according to the outcome of the neoadjuvant chemotherapy. Pathological complete response is considered when there is complete eradication of the local regional disease. Residual disease in the primary focus and/or axilla after preoperative chemotherapy is associated with poor prognosis. Standard preoperative and postoperative specimen collection, handling, processing, and examination are essential components of proper evaluation and reporting of pathologic response to neoadjuvant chemotherapy.