Postoperative delirium is a common complication after colorectal cancer surgery that hinders recovery. This observational study hypothesizes that a simple, practical risk tool can be developed by combining preoperative clinical conditions, blood tests (including the TyG index), and clinical subtypes identified via clustering analysis. Investigators will enroll patients undergoing elective colorectal cancer surgery, assess delirium twice daily for 7 days postoperatively using the 3D-CAM, and finalize the scoring scale. It will help doctors quickly identify high-risk patients for targeted care to improve recovery. Only data will be collected; patients receive standard clinical treatment.