Clinical importance of discordance in hormone receptor and HER2/NEU status after neoadjuvant chemotherapy in breast cancer

Aim: Neoadjuvant chemotherapy (NAC) is used longer for both locally advanced breast cancer and early stage to increase breast conservation. Discordance of the hormone receptor (HR) status was reported to be 8-33% of the breast cancer after NAC. The aim of this study was to compare the HR and HER2/neu status between core needle biopsy (CNB) and residual tumour after surgery of breast cancer treated with NAC and also to evaluate effect of discordance and other clinicopathological factors on survival.