The purpose of this study is to study the law of intramural diffusion of low rectal cancer in different stages, and to explore the relationship between intramural diffusion of low rectal cancer and the distal resection margin during operation, so as to provide theoretical basis for clinicians to formulate accurate and individualized treatment plans, and help improve the prognosis and quality of life of patients.

• Inclusion criteria

  1. Patients aged 18-75 years old
  2. Pathology suggestive of moderately to highly differentiated rectal adenocarcinoma
  3. Tumor lower margin ≤ 5 cm from the anal verge
  4. No distant metastasis such as lung, liver and other organs

• exclusion criteria

  1. Preoperative patients with severe underlying diseases (such as severe liver and kidney function, cardiopulmonary function, coagulation dysfunction, etc.)
  2. Patients with malignant tumors in other parts of the body

Patients with ultra-low rectal cancer