SCRT + mFOLFOX6 + PD-1 Antibody + Targeted Therapy for HIgh-Risk pMMR/MSS Rectal Cancer

This study is testing a combination treatment approach for high-risk rectal cancer — short-course radiation followed by chemotherapy plus an immunotherapy drug and a targeted therapy drug — before surgery, to see if this improves outcomes compared to standard care. **You may be eligible if...** - You are between 18 and 75 years old - You have been diagnosed with rectal cancer (a specific molecular subtype called pMMR/MSS) confirmed by biopsy - Your tumor is within 10 cm of the anal opening - Your cancer is locally advanced with specific high-risk features on imaging - Your cancer has not spread to distant organs - You have not had any prior cancer treatments (chemotherapy, radiation, immunotherapy, or targeted therapy) - You are in good overall health **You may NOT be eligible if...** - You have already received cancer treatment - Your cancer has spread to other parts of the body - You have a different molecular type of rectal cancer Talk to your doctor to see if this trial is right for you.