A small difference in decision-making causes a big impact on the long-term outcome in cancer treatment. Novel methods such as preoperative systemic treatment or sentinel node biopsy (SNB) may alter the decision-trees in primary breast cancer management. Recent data showed that preoperative chemotherapy drives pathological complete response (pCR) that implies long-term relapse-free, for about 25% to 30% of early breast cancer patients. In fact, preoperative systemic therapy has come to be used regardless of the tumor stage. From the point of the clinical trial, pCR can be recognized as a new endpoint, which promises to speed up new therapy development. Therefore, it is crucial to consider new paradigms including preoperative therapy in the decision-tree. There are several criticisms regarding the preoperative therapy, such as a possibility of over-treatment, however these issues might be resolved by changing the concept or procedures slightly. For instance, if SNB is conducted before the treatment, the over-treatment issue can be eliminated. In this article, we will discuss the changes in decision-tree and paradigms for primary