Application of Left Colic Artery Preservation, Anastomotic Reinforcing Sutures and Transanal Tube in Robotic Low Anterior Resection

Inclusion Criteria: * Clinical diagnosis of low rectal cancer; Low rectal cancer was defined by the presence of the inferior pole of the tumor below the peritoneal reflection (in 11 cm from the anal margin) * Primary tumor has undergone histologically comfirmed rectal adenocarcinoma * Together with clinical or radiological evidence of Stage II (T3-4, N0, M0) or Stage III (T1-4, N1-2, M0) disease (according to the 2016 revision of the International Union Against Cancer primary tumor, regional nodes, metastasis (TNM) staging system) * Performance status (ECOG) 0\~1 * Adequate hematological function: Neutrophils≥1.5 x109/l and platelet count≥100 x109/l; hemoglobin (Hb) ≥9g/dl (within 1 week prior to randomization) * Adequate hepatic and renal function: Serum bilirubin≤1.5 x upper limit of normal (ULN), alkaline phosphatase ≤5x ULN, and serum transaminase (either primary tumor, regional nodes, metastasis (AST) or ALT) ≤ 5 x ULN(within 1 week prior to randomization); * Written informed consent for participation in the trial. Exclusion Criteria: * Body mass index (BMI) more than 30 kg/m2 * Serious pre-operative comorbidity, including cardiovascular disease (coronary arteriosclerosis, arrhythmia, heart failure), pulmonary dysfunction (lung emphysema, obstructive lung disease), liver insufficiency (Child-Pugh B or C), renal insufficiency (serum creatinine \>2.0 mg/dl), and arterial circulation disturbance (occlusion of arterial vessels of limb in patient's history * History of accepting abdominal surgery