Table 1 Inclusion, exclusion, and withdrawal criteria

• 18 years < age < 80 years

• BMI > 30 kg/m²

• Invasion of adjacent structures or distant metastasis

• Tumor located in the rectosigmoid (defined as 10 to 30 cm from the anal verge, measured via colonoscopy or EUS)

• Pregnant or lactating women

• Inability to undergo surgery or anesthesia because of a changing illness state

• Pathological rectosigmoid cancer

• Severe mental disease

• Changing illness state requires an emergency operation

• Clinically diagnosed cT1-4aN0-2 M0 lesions according to the 7th Edition of the AJCC Cancer Staging Manual (measured using abdominal CT and colonoscopy or EUS)

• Previous abdominal surgery (except extraperitoneal surgery)

• Intraoperative colon irrigation

• Tumor size of 5 cm or less

• Emergency operation to treat complications (bleeding, perforation, or obstruction) caused by colorectal cancer

• Serious protocol violations

• ECOG performance status of 0 to 1

• Need for simultaneous surgery for another disease

• Patient required to withdraw

• ASA classification I to III

• Malignant disease within the previous 5 years (except superficial squamous or basal cell cancer of the skin or in situ cancer of the cervix)

• Informed consent

• Nonspeaker of Chinese or English