Modified Short-Course Radiation Combined With CAPOX and Tislelizumab for MSS Locally Advanced Middle and Low Rectal Cancer An Open-Label, Single-Arm, Prospective Multicenter Clinical Trial

What this Trial Is About

Researchers are evaluating a new treatment approach for patients with middle and low rectal cancer that is microsatellite stable (MSS). This phase II clinical trial aims to assess a modified short-course radiation therapy that targets only the tumor bed without affecting nearby tumor-draining lymph nodes. The study combines this radiation with chemotherapy drugs CAPOX and the PD-1 inhibitor Tislelizumab. The main goal is to measure the rate of complete tumor disappearance after surgery, along with organ preservation, tumor shrinkage, long-term outcomes, and side effects. The treatment includes a modified short-course radiotherapy delivering 25 Gy over 5 sessions focused on the tumor bed. Patients receive chemotherapy with Capecitabine (1000 mg/m2 daily for 14 days every 3 weeks) and Oxaliplatin (130 mg/m2 on day 1 every 3 weeks) alongside the PD-1 antibody Tislelizumab (200 mg on day 1 every 3 weeks). This combined approach is given before surgery to test its effectiveness and safety. Participants will be monitored closely throughout the study, with assessments including imaging and pathological analysis of tissue after surgery to determine treatment response. Researchers will track outcomes such as the complete response rate within 10 days after surgery, organ preservation rates, tumor regression grades, long-term prognosis, and adverse effects. The trial will enroll 32 patients aged 18 to 75 who meet specific health and cancer criteria and will follow them during and after treatment for comprehensive evaluation.

Nodes-sparing Short-course Radiation Combined With CAPOX and Tislelizumab for MSS Middle and Low Rectal Cancer