Although neoadjuvant chemoradiotherapy has significantly reduced the risk of local recurrence in locally advanced rectal cancer, systemic failure remains a predominant issue probably due to the insufficient control of systemic micro-metastasis in the neoadjuvant treatment. Induction chemotherapy is one of the most studied strategies. However, the efficacy of induction chemotherapy prior to neoadjuvant chemotherapy remains controversial. In our previous study, induction chemotherapy, gap chemotherapy combined with neoadjuvant chemoradiotherapy can improve response rate of rectal cancer patients, but the results have not been confirmed in clinical trial. Whether this new kind of treatment can optimize neoadjuvant therapy for locally advanced rectal cancer or not is still a big problem in clinical practice. This study will focus on how to optimize neoadjuvant chemotherapy.