Preoperative systemic therapy has provided novel insights into the treatment of primary breast cancer. The knowledge of the response to the treatment helps to predict long-term survival outcome, which indicated that the patients who benefit from the treatment are identifiable at individual level. The subgroup with pathological complete response (pCR) to the preoperative chemotherapy (Pre-CT) shows a favorable prognosis, whereas the subgroup with non-pCR shows an unfavorable prognosis. These identifications enable to classify the patients into multiple categories and to consider novel therapeutic implication more efficiently and more individually. Theoretically in the preoperative treatment system it is possible to distinguish the patients who require novel therapy beyond the conventional therapy from those require no further systemic chemotherapy except the conventional therapy or those who need no systemic chemotherapy. Novel therapy development specific for non-pCR patients should be considered in the future clinical trials. In this review, we will focus on these insights elicited by Pre-CT in primary breast cancer treatment.