Abstract: Objective The aim of this study was to explore the changes of tumor histopathological information of breast cancer before and after neoadjuvant chemotherapy and its effect on prognosis.Methods A retrospective analysis of 177 patients with breast cancer undergoing neoadjuvant chemotherapy who were admitted to the Department of Breast Surgery of Liaoning Cancer Hospital from January 2014 to May 2016 was conducted to determine the changes of tumor histopathological information before and after neoadjuvant chemotherapy.The effects of residual tumor histopathological information on disease-free survival(DFS)and overall survival(OS)were analyzed.Results The median follow-up time of 177 breast cancer patients was 37 months.The 37-month disease-free survival rate and overall survival rate were 84.0% and 95.0%,respectively.The 4-year disease-free survival rate and overall survival rate were 79.7% and 81.1%,respectively.The independent risk factors of DFS in breast cancer patients after neoadjuvant therapy were the original T stage,the original N stage,the presence of vascular invasion,and increasing Ki-67 after neoadjuvant chemotherapy.The independent risk factors of OS were the original T stage and the original N stage.The changes of ER status,PR status and HER-2 status before and after neoadjuvant chemotherapy were not related to the prognosis of patients(P＞0.05).Conclusion The molecular biological indexes ER,PR,HER-2 and Ki-67 can be changed for breast cancer before and after neoadjuvant chemotherapy,but it has nothing to do with the prognosis of breast cancer patients.The T stage of the original tumor,the N stage of the original tumor,the presence of vascular invasion and the increasing Ki-67 are the risk factors that affect the DFS of patients with breast cancer.The original tumor T stage and N stage are the risk factors that affect the OS of patients with breast cancer.

Key words: Breast cancer, Neoadjuvant chemotherapy, Molecular biological indicators, Prognosis