Rectal cancer is primarily treated with surgery, including low anterior resection or ultra-low anterior resection depending on tumor characteristics. Anastomotic leakage is one of the most serious postoperative complications and is associated with increased morbidity and mortality. Established risk factors include male sex, preoperative radiotherapy, low anastomosis, advanced age, comorbidities, and vascular disease.

Atherosclerosis may contribute to anastomotic leakage by reducing blood flow and impairing tissue perfusion at the anastomotic site. The inferior mesenteric artery (IMA), a major source of blood supply to the colorectal region, may be affected by atherosclerotic narrowing or occlusion, potentially increasing the risk of postoperative leakage.

The aim of this study is to assess the degree of IMA occlusion using routine preoperative contrast-enhanced computed tomography (CT) scans obtained for rectal cancer staging and to investigate its association with anastomotic leakage after rectal cancer surgery. Identification of patients with severe IMA occlusion may help guide the selective use of protective stomas to reduce the risk of this complication.

Rectal cancer can be diagnosed either after the onset of symptoms or through screening of asymptomatic individuals. Although surgery remains the cornerstone of curative treatment, rectal cancer may be managed with local excision or radical resection depending on the clinical stage, size, and location of the tumor. In terms of radical resection, patients may undergo low anterior resection or ultra-low anterior resection.

Anastomotic leakage is a serious complication following rectal surgery and is associated with increased morbidity and mortality. Elderly patients and those with comorbidities have a higher risk of death after the occurrence of an anastomotic leak. The main risk factors for anastomotic leakage include male sex, preoperative radiotherapy, low anastomosis (less than 10 cm from the anal verge), a high burden of comorbidities, advanced age, and a history of vascular disease.

Atherosclerosis increases the risk of anastomotic leakage by causing inadequate perfusion of the anastomosis due to tissue ischemia and impaired microcirculation. When atherosclerosis develops, the intima of the arteries thickens, the vessel lumen narrows, blood flow decreases, and the vasomotor function of blood vessels is impaired. In addition, collateral circulation is reduced, thereby increasing the risk of anastomotic leakage.

The superior mesenteric artery and inferior mesenteric artery are primarily responsible for the blood supply to the colorectal region. During colorectal surgery, the normal blood flow to the bowel is disrupted and reduced, which may result in local intestinal ischemia.

The primary aim of our study is to evaluate and grade the diameter of the inferior mesenteric artery using preoperative contrast-enhanced computed tomography, a simple, rapid, and readily available imaging modality routinely performed for staging purposes in patients with rectal cancer. By identifying patients with a high degree of inferior mesenteric artery narrowing or occlusion, we aim to determine whether the creation of a protective stoma should be recommended to reduce the risk of postoperative anastomotic leakage following rectal cancer surgery.

Inclusion Criteria:

• ICD C20 Patients diagnosed with malignant neoplasm of the rectum
• Patients who have undergone laparoscopic or open surgery with low anterior resection or ultra low anterior resection due to rectal cancer

Exclusion Criteria:

• Patients with a history of abdominal aorta surgery/grafting
• Patients diagnosed with vascular, autoimmune, or rheumatological diseases.

Adult patients who have undergone low/ultra-low anterior resection due to rectal cancer.

Individual participant data will not be shared due to patient confidentiality and institutional data protection policies.