Prospective Phase II Study on Continuous Circumferential Reinforcement of Laparoscopic Rectal Anastomosis to Prevent Complications

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.