Robotic Transanal Specimen Extraction Surgery Versus Robotic Transabdominal Incision Specimen Extraction Surgery for Patients With Rectal Cancer: A Multicenter Randomized Controlled Trial

Inclusion Criteria:

1. Age between 18 to 75 years;
2. Historically confirmed rectal adenocarcinoma;
3. Diagnosed with rectal cancer by pelvic/rectal magnetic resonance imaging;
4. cT1-4aNxM0 high rectal adenocarcinoma; cT1-3NxM0 mid/low rectal adenocarcinoma;
5. No evidence of distant metastases;
6. A maximum of 5cm in diameter;
7. Body mass index (BMI) ≤ 30 kg / m2;
8. No local complications (no obstruction, incomplete obstruction, no massive active bleeding, no perforation, preoperatively abscess formation, no local invasion);
9. Willing to undergo surgery;
10. Sign the informed consent;

Exclusion Criteria:

1. Presence of lateral/inguinal lymph node metastases;
2. Previous history of malignant colorectal tumor;
3. Multiple primary colorectal tumors;
4. Neoadjuvant therapy;
5. Salvage surgery for endoscopic surgery;
6. History of previous abdominopelvic surgeries or extensive intra-abdominal adhesion;
7. Familial adenomatous polyposis, Lynch syndrome, and inflammatory bowel disease;
8. Comorbid with other malignancies within 5 years;
9. ASA ≥ IV and/or ECOG performance status score ≥ 2;
10. Severe liver, kidney, cardiopulmonary insufficiency, coagulopathy or serious underlying diseases;
11. Serious mental illness;
12. Pregnant or lactating women;
13. Uncontrolled infection;
14. Abnormal anal function or anal stenosis;