Phase II Trial of MR-guided Adaptive Radiotherapy with PD-1 Antibody and CAPOX for Treating Locally Advanced Rectal Cancer

What this Trial Is About

Researchers are evaluating a new treatment approach for patients with locally advanced rectal cancer LARC characterized by specific tumor stages T3-4NM0 and tumor location within 12 cm from the anal verge. This phase II, prospective, randomized trial aims to assess the pathological complete response pCR rate following combined therapies. Secondary goals include monitoring severe acute side effects, anal function, surgical complications, and survival rates over three years. Participants will receive MR-guided adaptive radiotherapy at a dose of 30 Gy administered in 6 fractions, combined with six cycles of the chemotherapy regimen CAPOX and the PD-1 antibody Toripalimab. There are two experimental groups one receiving conventional pelvic radiotherapy and the other undergoing lymph node-sparing radiotherapy, both followed by total mesorectal excision TME surgery after total neoadjuvant therapy TNT. Treatment dosing schedules include Toripalimab at 240 mg every three weeks, Oxaliplatin at 130 mgm2 every three weeks, and Capecitabine at 1000 mgm2 twice daily for 14 days every three weeks. During the study, participants will undergo regular assessments to monitor treatment effects, including pathological evaluation one month after surgery to determine pCR. Researchers will also track grade 3-4 adverse events from randomization until three months post-neoadjuvant therapy, anal function and local recurrence-free survival up to 36 months, as well as disease-free and overall survival rates over three years. Surgical complications will be evaluated within three months after surgery. The total duration of participation includes treatment, surgery, and follow-up assessments for up to three years.

MR-guided Adaptive Radiotherapy Combined With PD-1 Antibody and CAPOX for Locally Advanced Rectal Cancer