This study compared robot-assisted total mesorectal excision (RTME) and laparoscopic total mesorectal excision (LTME) with regard to urinary function, sexual function and sphincter- preservation outcomes for low rectal cancer.

Urinary and sexual dysfunction are recognized complications of rectal cancer surgery in men. This study compared robot-assisted total mesorectal excision (RTME) and laparoscopic total mesorectal excision(LTME) with regard to these functional outcomes.Sphincter- preservation outcomes for low rectal cancer was observed as well.

Inclusion Criteria:

• 1. Patients who are acceptable to two surgical procedures for the robot- assisted or laparoscopy-assisted rectal cancer, are willing to randomized trial;
• 2. Matching the diagnostic criteria;
• 3. Aged 18-70 years old;
• 4. Preoperative TNM staging (CT, laparoscopic exploration): cT1-3N0-3M0 (excluding M1, T4);
• 5. Preoperative ASA 3 scores;
• 6. There was no history of malignancy, no other malignant tumors by preoperative examination;
• 7. Without undergoing definitive treatment, such as radiotherapy, chemotherapy or immunotherapy preoperatively;
• 8. The informed consent form was signed by the patient himself(herself)or his principal agent;
• 9. In accordance with the international erectile function questionnaire (IIEF) urinary function scale, The urinary sexual function are normal.

Exclusion Criteria:

• 1. Age less than 18 years old or more than 70 years old;
• 2. Previous psychiatric patients or patients refused to sign the informed consent;
• 3. Attending other related clinical studies on surgical treatment of rectal cancer;
• 4. The patient has a history of malignant tumor, or a combination of other malignant tumors;
• 5. Patients have been treated with definitive treatment: radiotherapy, chemotherapy or immunotherapy;
• 6. Patients had received otherper abdominal operations (except for laparoscopic cholecystectomy);
• 7. ASA >3;
• 8. Laparoscopic surgical contraindications: such as severe heart lung disease; abdominal wall hernia; diaphragmatic hernia; coagulation disorder; portal hypertension; pregnancy, etc.;
• 9. Those who has been confirmed to be unable to do a radical resection (T4 stage) for local advanced tumor;
• 10. Those who have urination sexual dysfunction preoperatively.