- 1. Clinical stage II or stage III rectal cancer patients diagnosed by preoperative biopsy pathology report, endoscopic examination report and preoperative abdominal pelvic dynamic contrast enhanced-MRI examination (DCE-MRI); 2. Primary tumor lesions within 4~12 cm from the anus through endoscopic examination; 3. No distant metastasis and intestinal obstruction; 4. No surgical contraindications; 5. Can be treated with neoadjuvant chemotherapy confirmed by normal routine examination; 6. informed consent with patients and family members before treatment.