SCRT Based iTNT vs. LCRT Based TNT for MSS Locally Advanced Rectal Cancer

In this prospective, multicentre, randomized phase III trial, 612 locally advanced rectal cancer (LARC, T3-4/N+M0) patients with at least one high-risk features (lower location (≤5cm), cT4, cN2, MRF+, EMVI+, TD+) will be included, and randomly assigned to TNT group and iTNT group (1:1). TNT group receives long-course chemoradiotherapy (50Gy/25Fx concurrent with oral capecitabine) followed by 6 cycles of CAPOX. iTNT group receives short-course radiotherapy (25Gy/5Fx) followed by 6 cycles of Serplulimab combined with CAPOX. After the efficacy evaluation, the patients who achieves clinical complete response (cCR) will be managed by a watch and wait (W\&W) protocol and non-cCR patients will be recommended surgery. The primary endpoint is 3-year event-free survival rate (3yEFS%). The secondary endpoints include the complete response (CR, pathological complete response \[pCR\] plus cCR) rate, 3-year organ preservation rate, 3-year disease-free survival rate (3yDFS%), 3-year local recurrence free survival rate (3yLRFS%), 3-year distant metastasis free survival rate (3yDMFS%), 3-year overall survival rate (3yOS%), grade 3-4 acute adverse effects (AE) rate, rate of surgical complications, anal functions and quality of life, etc.