The intraductal component of breast cancer is poorly responsive to neo-adjuvant chemotherapy.

Neo-adjuvant chemotherapy has been used for locally advanced breast cancers. With special attention to the proportion of intraductal component, we pathologically studied 25 patients that underwent neo-adjuvant chemotherapy via intra-arterial infusion or intravenous injection. In general, neo-adjuvant chemotherapy had a favorable effect on tumor reduction. The effectiveness varies depending on the predominance of intraductal component. The cases with a high proportion of intraductal component had lower response to the chemotherapies. The larger number of cancer cells remained within the mammary ducts. The residual cancer cells conserved proliferative activity. Intraductal component is poorly responsive to neoadjuvant chemotherapy.