Research progress of neoadjuvant therapy for locally advanced rectal cancer

Abstract

The clinical application of novel chemotherapeutic drugs including oral 5-FU and targeted drugs and preoperatively accurate imaging grading has brought challenges to the indication criteria developed by NCCN and ESMO for neoadjuvant chemoradiotherapy in locally advanced rectal cancer (LARC). Extended hotspots have focused on the effectiveness of using capecitabine instead of fluorouracil infusion, the combination of multiple drugs and the feasibility of using neoadjuvant chemotherapy instead of neoadjuvant chemoradiotherapy for selective patients. Traditionally, the evaluation of the effect of neoadjuvant therapy has been based on the effect on the pathological complete remission (pCR) rate. However, current studies recommend the disease-free survival (DFS) as a more important outcome. Besides, seeking for effective biomarkers as predictive markers for neoadjuvant therapies or as prognostic markers remains a hotspot in the field of neoadjuvant chemoradiotherapy. The "watch and wait" approach refers to taking a close follow-up strategy instead of direct operation for patients achieving clinically complete remission (cCR) after neoadjuvant therapy. However, there is no unified evaluation criteria and time point for the evaluation of cCR following neoadjuvant therapy. Therefore, there remain a lot of controversies regarding the clinical application of neoadjuvant chemoradiotherapy in LARC. In this manuscript, research progress in the indication for neoadjuvant therapy, improvement in the neoadjuvant therapeutic schedule, advancement of the efficacy evaluation criteria of neoadjuvant therapy, the "watch and wait" approach and other hot topics is summarized to provide references for clinical practice.