The goal of this clinical trial is to evaluate the safety and efficiency of stent-based tiverting technique (SDT) versus ileostomy in rectal cancer patients. After the removal of the rectal tumor, participants who are at high risk for anastomotic leakage will either undergo SDT or ileostomies. Researchers will compare SDT to see if SDT could help patients save hospital stays, lower medical costs, and enhance their quality of life, and not alternatively avoid defunction stoma.

In patients with rectal cancer who have a high risk of anastomotic leakage, we aim to compare the safety and effectiveness of SDT versus ileostomy in this study. The primary endpoint of the study was severe complications that occurred within 90 days of the surgery. The secondary endpoints included total complications, the incidence of coloanal anastomotic leakage (Grade B/C), postoperative hospital stay and cost, and postoperative quality of life evaluation.

Inclusion Criteria:

1. Rectal adenocarcinoma confirmed pathologically.
2. Rectal cancer patients with high-risk of anastomotic leakage(AL).
3. Age from over 18 to under 80 years.
4. Performance status of 0/1 on ECOG (Eastern Cooperative Oncology Group) scale.
5. ASA (American Society of Anesthesiology) score class I, II, or III.
6. Written informed consent.

Definition of high-risk of AL (one of them):

1. Preoperative body mass index (BMI) ≥30 kg/m2;
2. Long-term use of glucocorticoids before surgery (≥2 weeks);
3. Poor general condition: Preoperative serum albumin was less than 30.0g/L after supportive treatment; or Preoperative renal replacement therapy (blood purification/hemodialysis) is required; or diabetes;
4. Preoperative neoadjuvant radiotherapy;
5. Distance between tumor and anal anus (baseline MRI) ≤7cm
6. The number of stapler used to cut the rectum during the operation ≥3; or the defect of anastomosis is observed; or Intraoperative leak test was positive.

Exclusion Criteria:

1. History of previous rectectomy, except endoscopic mucosal resection or endoscopic submucosal dissection.
2. Familial Adenomatosis Polyposis Coli (FAP), Hereditary Non-Polyposis Colorectal Cancer (HNPCC), active Crohn's disease or active colitis ulcerosa.
3. History of unstable angina, myocardial infarction, cerebrovascular accident within the past six months.
4. Groups who are particularly vulnerable include those who suffer from mental disease, cognitive impairment, severe illness, adolescents, illiterates, women during pregnancy or breast-feeding, etc.
5. Patients with severe complications who do not tolerate surgery or need emergency surgery due to complication (bleeding, obstruction or perforation)
6. Unable ot radical resection, or underwent Miles or Hartmann or TaTME procedure, or requirement of simultaneous surgery for other disease (except the gallblader or appendix due to benign lesion).

The data are available from the Principal Investigator upon reasonable request.

The masking in this study is inappropriate because the patients in the SDT group do not have an abdominal stoma.