Anastomotic leakage (AL) is one of the most severe complications following laparoscopic rectal cancer surgery. According to the International Study Group of Rectal Cancer (ISREC), AL is defined as a defect of intestinal wall integrity at the colorectal or coloanal anastomosis leading to a communication between the intra- and extraluminal compartments, including defects of the suture or staple lines of the neorectal reservoir. AL is classified into three grades based on clinical severity: Grade A, identified only radiologically without clinical symptoms; Grade B, presenting with localized or atypical peritonitis requiring antibiotics and local drainage but not surgery; and Grade C, causing severe peritonitis, systemic toxicity symptoms requiring urgent surgical intervention, and potentially leading to life-threatening situations.

AL can prolong hospitalization, necessitate reoperation, delay chemotherapy, increase local recurrence rates, and adversely affect survival and quality of life. Emergency surgical management of AL often requires meticulous peritoneal lavage and ileostomy, aiming for subsequent anastomotic healing or future digestive tract reconstruction. However, some patients face significant challenges due to postoperative adhesions and persistent anastomotic defects despite prolonged lavage.

Identified risk factors for AL after rectal cancer surgery include male gender, advanced age, hypertension, diabetes, smoking, and advanced TNM staging (III-IV). Additionally, preoperative chemoradiotherapy-induced bowel edema and fibrosis, bowel obstruction, and long-term malnutrition resulting in hypoproteinemia are significant contributors. Mechanical reinforcement of anastomoses using sutures or absorbable barbed sutures has been shown to significantly reduce AL rates in previous studies.

This single-center prospective phase II clinical trial aims to evaluate the efficacy and safety of continuous circumferential reinforcement using absorbable barbed sutures in laparoscopic rectal anastomosis to prevent AL. We will compare the incidence of AL and other postoperative complications between patients undergoing reinforced anastomosis and a control group receiving standard laparoscopic rectal anastomosis.

Inclusion Criteria:

Histological Confirmation:

Diagnosed with rectal adenocarcinoma confirmed by histology.

Tumor Location:

MRI confirms a mid to upper rectal tumor, with the lower margin of the tumor located 6-12 cm from the anal verge.

Preoperative Staging:

Preoperative MRI staging indicates the presence or absence of MRF positivity and/or EMVI positivity; the surgical team assesses the tumor as resectable with an estimated R0 resection.

Bowel Obstruction:

No signs of bowel obstruction.

Neoadjuvant Chemoradiotherapy:

For patients who have received neoadjuvant chemoradiotherapy, complete radiotherapy and baseline imaging records must be available at this center.

Previous Treatments:

Surgical History:

No previous colorectal surgery.

Biological and Immunotherapy:

No prior treatment with biological drugs (e.g., monoclonal antibodies), immunotherapy (e.g., anti-PD-1 antibodies, anti-PD-L1 antibodies, anti-PD-L2 antibodies, or anti-CTLA-4), or other investigational drugs.

Endocrine Therapy:

No restrictions on prior endocrine therapy.

Patient Characteristics:

Age:

Between 18 and 75 years old.

Performance Status:

ECOG performance status of 0-1 (see Appendix 3).

Life Expectancy:

Greater than 2 years.

Hematological Parameters:

WBC > 3×10^9/L; PLT > 80×10^9/L; Hb > 90 g/L.

Liver Function:

ALT and AST less than 2 times the upper limit of normal; bilirubin less than 1.5 times the upper limit of normal.

Renal Function:

Creatinine less than 1.5 times the upper limit of normal or creatinine clearance (CCr) ≥ 60 ml/min.

Exclusion Criteria:

Patients meeting any of the following conditions will be excluded from the study:

Need for Multiorgan Resection:

Patients requiring combined organ resection.

Preventive or Permanent Stoma:

Patients requiring preventive or permanent stoma.

Hartmann or Miles Procedures:

Patients requiring Hartmann's procedure or Miles' surgery.

Cardiac Conditions:

Arrhythmias requiring antiarrhythmic treatment (excluding β-blockers or digoxin), symptomatic coronary artery disease, localized myocardial ischemia (myocardial infarction within the last 6 months), or congestive heart failure beyond NYHA Class II.

Uncontrolled Hypertension:

Severe hypertension that is not well controlled by medication.

Infectious Diseases:

History of HIV infection or active chronic hepatitis B or C with high viral DNA copies.

Active Tuberculosis (TB):

Subjects with active pulmonary tuberculosis, currently undergoing anti-tuberculosis treatment, or having received anti-tuberculosis treatment within 1 year prior to screening.

Severe Infections:

Other active clinically severe infections (according to NCI-CTC version 5.0).

Evidence of Distant Metastasis:

Preoperative evidence of distant metastasis outside the pelvis.

Cachexia and Organ Failure:

Cachexia or decompensated organ function.

Radiotherapy History:

History of pelvic or abdominal radiotherapy.

Multiple Primary Colorectal Cancers:

Presence of multiple primary colorectal cancers.

Seizure Disorders:

Patients with seizures requiring treatment (e.g., steroids or antiepileptic therapy).

History of Other Malignancies:

History of other malignancies within the past 5 years, except for cured in situ cervical cancer or basal cell carcinoma of the skin.

Substance Abuse:

Substance abuse or medical, psychological, or social conditions that could interfere with the patient's participation in the study or the evaluation of study results.

Allergies:

Known or suspected allergies to the investigational drug or any drug related to the study.

Unstable Conditions:

Any unstable condition or situation that might jeopardize patient safety and compliance.

Pregnancy or Lactation:

Women who are pregnant or breastfeeding, and women of childbearing potential not using adequate contraceptive measures.

Informed Consent:

Refusal to sign the informed consent form.