Organ Preservation First Strategy and Intentional Watch and Wait for MRI Defined Low-risk Rectal Cancer

The goal of this clinical trial is to test the safety and efficacy of local excision (LE) or non-operative management (NOM) in patients with MRI defined low-risk rectal cancer following neoadjuvant intensity modulated radiotherapy with concurrent capecitabine plus consolidation CapeOX. The main questions it aims to answer are: 1. What is the organ-preservation rate (OPR) after in patients with MRI defined low-risk rectal cancer following neoadjuvant intensity modulated radiotherapy with concurrent capecitabine plus consolidation CapeOX? 2. Is LE or NOM safe and effective in patients with MRI defined low-risk rectal cancer following neoadjuvant intensity modulated radiotherapy with concurrent capecitabine plus consolidation CapeOX? Participants will receive radical surgery, LE, or NOM based on the response of neoadjuvant intensity modulated radiotherapy with concurrent capecitabine plus consolidation CapeOX in patients with MRI defined low-risk rectal cancer.