Comparison of Postoperative Anal Function Between Parks and Bacon Techniques in Low Rectal Cancer

objective: To compare the postoperative anal function of patients with ultra-low rectal cancer after Parks operation (colon anal anastomosis) and Bacon operation (colon anal pull-out anastomosis), which may provide clinical evidence for the improvement of anal function and quality of life.

primary outcome: Low Anterior Resection Syndrome (LARS) score 1 year after surgery secondary outcomes: 1. LARS score at 3 months after surgery 2. LARS score at 6 months after surgery 3. Postoperative Quality of Life Score 4. The incidence of postoperative anastomotic complications

Inclusion criteria

• Men or women, aged between 18 and 75 years;
• Pathological diagnosis of rectal cancer before operation, with the distance from the lower edge of the tumor to the dentate line ≤ 3cm by MR imaging;
• No local complications (including complete/ incomplete obstruction, active bleeding, local invasion of sphincter or levator ani, etc.) before operation;
• Suitable for anal preservation surgery discussed by MDT;
• Adequate bone marrow, liver, renal and cardiac function meeting the requirements of surgery and anesthesia;
• R0 resection is expected technically;
• Provision of written informed consent.

Exclusion criteria

• Previous history of malignant colorectal tumors;
• Complications such as obstruction and gastrointestinal bleeding that need an emergency operation;
• Unachievable R0 resection due to invasion of adjacent organs by primary tumor;
• Multiple primary tumors;
• History of other malignancy;
• Participation in other clinical trials within the previous 4 weeks of enrollment;
• ASA physical status score ≥ IV level and/or ECOG performance status ≥ 2;
• Intolerance of surgery due to liver, renal, cardiopulmonary or coagulation dysfunction, or underlying diseases;
• History of serious mental disorders;
• Women in pregnancy or lactation period;
• Uncontrolled infection before operation;
• Unsuitable to be included due to other clinical and laboratory conditions by the judgement of investigators.