Radiotherapy is a commonly used treatment for many kinds of malignant tumors. In the past, due to the poor therapeutic effect of malignant tumors and the short survival period of tumor patients, the chronic complications of radiotherapy, such as chronic radiodermatitis and chronic radial enteritis, have not attracted sufficient attention. With the continuous progress of tumor treatment and the gradual extension of survival time of tumor patients, chronic radiation enteritis has gradually become one of the factors affecting postoperative survival and quality of life of tumor patients, and this disease has been gradually recognized and valued by clinicians in recent years. In this article, we would like to briefly introduce chronic radiation enteritis, focusing on the surgical treatment of this disease. Etiology: Chronic radiation enteritis (CRE) is a complication that occurs after pelvic radiotherapy, and it is common in patients with cervical cancer, prostate cancer and rectal cancer who have received radiation therapy. The disease is mainly characterized by occlusive vasculitis of small submucosal arteries in the intestine and fibrosis of the intestinal wall caused by radiation, which ultimately leads to changes such as obstruction of the intestinal lumen and perforation of the intestinal wall lesions. The disease most often occurs 12-24 months after radiotherapy, but there are also reports of chronic radiation enteritis diagnosed as short as 3 months after radiotherapy and as long as 30 years after radiotherapy. The small intestine is the most sensitive to radiation, and the terminal small intestine, which is located in the pelvis and in a relatively fixed position, is the most vulnerable site for radiation injury, followed by the rectum and the sigmoid colon. The disease is related to the dose and method of radiotherapy, the higher the dose of radiotherapy, the higher the possibility of CRE, while measures such as conformal radiotherapy can reduce the irradiation dose to normal tissues, and drugs such as amifostine can protect normal tissues to reduce radiation damage. According to previous reports, its overall incidence is between 1.2% and 15%. Since the pathologic changes of CRE progressively worsen after radiotherapy, its symptoms become more and more severe over time. Clinical manifestations : Mild to moderate CRE often manifests as abdominal pain, diarrhea, mucous bloody stools, a sense of urgency and heaviness, etc. Internal medicine treatment is the mainstay, and can be treated with antidiarrheal, nutritive intestinal mucosa, microecological agents, etc. Surgical indications for CRE include intestinal stenosis and obstruction, intestinal fistula, intestinal perforation and severe intestinal bleeding, etc., of which intestinal obstruction accounts for about 70%, and intestinal fistula can be manifested as a tube connected with the surface of the body, the bladder, the vagina and so on. The possibility of CRE should be considered in patients with a history of pelvic radiotherapy who present with these symptoms. Colonoscopy can see radiation damage to the rectum, sigmoid colon or the last section of the ileum manifested as mucosal edema, pallor, granular surface, brittle, severe visible fistula, stenosis, etc.; gastrointestinal tract imaging can be found in the last section of the small intestine or colon of the intestinal lumen structural changes and stenosis.CT examination can be seen in the area of radiation therapy of the intestinal symmetric thickening or halo sign, walk stiffness, intestinal lumen stenosis, the leakage of the formation of tubes; enhancement of the CT visible Enhanced CT shows insignificant enhancement of the diseased intestinal segment, which is caused by occlusive vasculitis of the intestinal wall, and can be distinguished from malignant tumor recurrence. During the surgery, the intestinal tube of CRE can be seen to be pale, thickened and toughened with poor peristalsis, which is obviously different from the intestinal obstruction caused by tumor, inflammatory bowel disease, etc. Surgical characteristics: In the past, due to the less survival of patients with malignant tumors after radiotherapy and insufficient understanding of CRE, when patients with rectal cancer, cervical cancer, etc. have intestinal obstruction after surgery, after excluding tumor recurrence, they are often treated according to ” adhesive intestinal obstruction”, which is the most important feature. Adhesive bowel obstruction”. Whether it is adhesion or CRE, surgery should be performed when severe intestinal obstruction occurs, but distinguishing between adhesive intestinal obstruction and CRE is important for the timing and selection of surgical methods. The intestinal wall itself is usually healthy in mild adhesive bowel obstruction, and if the symptoms are relieved by short-term conservative treatment, observation can be continued; while CRE is a progressive aggravation of the lesion, once intestinal obstruction occurs, even if it is relieved by conservative treatment, it will surely be aggravated and recur in the future, and other complications, such as perforation, intestinal fistula, bleeding, etc., may occur. Adhesive intestinal obstruction surgery only requires resection of the lesion seen with the naked eye, and in some cases, only adhesion release is needed without resection of the intestinal segment; whereas the lesion and obstruction of CRE will gradually expand over time, and the scope of resection should be expanded appropriately, so as to prevent the remaining intestinal segments from recurring after the surgery and reopening. Adhesive intestinal obstruction after intestinal resection can be performed according to the general principle of intestinal anastomosis; while the characteristics of CRE determine its small bowel resection should be selected after the peristaltic direction of lateral anastomosis, if necessary, after sigmoid colon or rectal resection, some patients must do enterostomy. As the radiation may also cause skin damage, the surgical incision of CRE patients tends to heal poorly and is prone to poor incision healing, incisional infection, incisional hernia, etc., and the previous practice is to delay the removal of stitches or avoid the radiation area to make surgical incisions; our department implements laparoscopic surgical treatment in some cases, which can effectively avoid incisional complications due to the small trauma of the skin and avoidance of the radiation damage area. However, this technique cannot be promoted in primary hospitals because most CRE patients have repeated or multiple surgeries with heavy intestinal adhesions, which makes laparoscopic operation difficult and requires a high level of laparoscopic skills from the surgeons. As with normal gastrointestinal surgery, if the symptoms can be relieved by small bowel decompression, nutritional support and other measures to improve the general condition, it can make elective surgery safer and more reliable. Therefore, the surgical characteristics of CRE are summarized as follows: 1, patients with mild to moderate uncomplicated disease should be treated with internal medicine; 2, patients with intestinal obstruction, intestinal fistula and other complications of CRE should be operated aggressively; 3, the scope of resection should be enlarged appropriately in the surgery of CRE, and the lateral anastomosis or stoma in the direction of peristalsis is the appropriate treatment; 4, laparoscopic surgery can effectively reduce or avoid the incisional complication.