Preservation Versus Excision of Denonvilliers Fascia in L-PANP Surgery

Inclusion Criteria: 1. Age from over 20 to under 60 years; 2. Primary rectal adenocarcinoma confirmed pathologically by endoscopic biopsy; 3. Mid-low rectal cancer (distance from anal edge≤12cm); 4. cT1-3, N0-3, M0 at preoperative evaluation according to the AJCC Cancer Staging Manual Seventh Edition; 5. Expected curative resection through L-PANP; 6. Performance status of 0 or 1 on ECOG (Eastern Cooperative Oncology Group) scale; 7. ASA (American Society of Anesthesiology) score class I, II, or III; 8. Written informed consent; 9. Urinary and sexual function normal preoperatively Exclusion Criteria: 1. Severe mental disorder; 2. History of previous pelvic surgery; 3. Enlarged or bulky regional lymph node diameter over 3cm by preoperative imaging; 4. History of other malignant disease within past five years; 5. History of unstable angina or myocardial infarction within past six months; 6. History of cerebrovascular accident within past six months; 7. History of continuous systematic administration of corticosteroids within one month; 8. Contraindication of heart, brain, lung, etc dysfunction; 9. Requirement of simultaneous surgery for other disease; 10. Emergency surgery due to complication (bleeding, obstruction or perforation) caused by rectal cancer; 11. Rectal cancer invades surrounding tissues; 12. Existence of genuine incontinence or severe stress incontinence preoperatively