This study is designed to evaluate the safety and efficacy of single-port robotic surgery compared to multi-port robotic surgery for rectal cancer.

Surgical robots were born in the 1980s and have the advantages of being precise, flexible, less invasive and remotely operable than traditional surgical methods. The single-port robot is a further extension of minimally invasive surgery by placing multiple instruments through a single incision. Most studies have reported on the perioperative outcomes of robotic versus conventional laparoscopic surgery in the treatment of colorectal cancer. However, there are limited data comparing the perioperative outcomes of single-port robotics and multi-port robotics in the treatment of colorectal cancer，especially in rectal cancer surgery. The purpose of this study is to evaluate the safety and efficacy of single-port robotic surgery compared to multi-port robotic surgery for rectal cancer.

Inclusion Criteria:

• 18 years < age ≤80 years
• Tumor located in the mid to high rectum (lower edge of tumor ≥ 5 cm from anal verge)
• Pathological rectal carcinoma
• Clinically diagnosed c/ycT1-3N0-1M0 lesions according to the 8th Edition of AJCC Cancer Staging Manual
• Tumor size of 10 cm or less
• No history of other malignant tumors
• ECOG score is 0-1
• ASA score is Ⅰ-Ⅲ
• Informed consent

Exclusion Criteria:

• Body mass index (BMI) >35 kg/m2
• Familial adenomatous polyposis (FAP)
• Inflammatory bowel disease (IBD)
• Multiple malignant colorectal tumors
• Pregnant woman or lactating woman
• Severe mental disease
• Previous gastrointestinal surgery (except appendectomy ）
• Combination of intestinal obstruction, bleeding, perforation requiring emergency surgery
• Requirement of simultaneous surgery for other disease
• Serious disorders of liver and kidney function, coagulation function, or severe underlying diseases that cannot tolerate the surgery.
• Patients or family members who cannot understand the study program.