Anastomotic leakage (AL) is one of the most-feared postoperative complications after anterior resection of rectal cancer. This complication compromises both short term and long term outcome of patients. The incidence of AL after anterior resection was approximately 6-11%. Although several risk factors for AL such as male sex, smoking, tumor location, longer operative time, intraoperative blood loss had been reported in previous studies, the incidence of AL did not meet a significant decrease. So far there is no multi-site observational study on incidence and risk factors of AL after anterior resection in China, therefore this study aims to work on this issue and provide evidence for clinical practice.

Inclusion Criteria:

• adenocarcinoma of the rectum by biopsy
• single lesion
• anterior resection was performed
• anastomosis using circular stapler

Exclusion Criteria:

• history of colorectal cancer surgery
• emergency surgery because of bowel obstruction, bleeding or perforation
• colo-anal anastomosis
• subtotal colectomy
• total colectomy
• abdominal perineal resection
• Hartmann procedure
• pull out anastomosis

Rectal cancer patients who underwent anterior resection with or without postoperative anastomotic leakage