To understand the current situation of the postoperative gastrointestinal dysfunction in patients with colorectal cancer effect a radical cure, and analyze the risk factors, and build the colorectal cancer radical surgery in patients with gastrointestinal dysfunction risk prediction nomogram model decision tree classification and regression tree model, through internal validation evaluation the performance of the two models in the modeling data set and dividing the postoperative gastrointestinal dysfunction risk level.Two risk prediction models were used to carry out external verification, evaluate the clinical practicability and effectiveness of the model, and provide reference for further promotion of the model.

Colorectal cancer is characterized by high morbidity and mortality. Surgical treatment is the main treatment for colorectal cancer. Surgery is the best treatment for long-term survival.

Surgery is a destructive operation, can lead to local tissue injury, physical barrier damage, causes the patient's body, and a series of metabolism, neuroendocrine and immune response, all of which can cause local inflammation or systemic inflammatory response, also leads to occurrence of related complications, such as abdominal and pelvic infection, fever, anastomotic infection and fistula, intestinal obstruction, etc., Thus increasing the risk of postoperative complications. The trauma and irritation of gastrointestinal tract caused postoperative gastrointestinal dysfunction.

The procedure of surgery is accompanied by anesthesia, and the anesthesia mode of gastrointestinal surgery is mainly general anesthesia. Opioid analgesics are one of the most important components of general anesthesia. The most common side effects of opioid analgesics include postoperative intestinal obstruction, nausea and vomiting, chills and urinary retention. The use of anesthetic drugs further aggravated the postoperative gastrointestinal dysfunction.

At the same time, laparoscopic surgery must establish pneumoperitoneum pressure. In recent years, studies have suggested that pneumoperitoneum pressure can lead to changes in the body's internal environment, resulting in a series of pathophysiological changes such as tissue ischemia, intestinal edema, and release of inflammatory factors in the gastrointestinal tract, resulting in dysfunction of gastrointestinal function.

All the above reasons lead to gastrointestinal dysfunction as the highest complication after radical resection of colorectal cancer.A review of previous literature shows that there is no predictive assessment tool for gastrointestinal dysfunction in patients after radical resection of colorectal cancer.Therefore, it is necessary to construct a risk prediction model for patients after radical resection of colorectal cancer, and to verify the clinical practicability of the model through external verification.

Inclusion Criteria:

• Patients aged ≥18 years;
• patients with diagnosed colon or rectal cancer;
• Patients diagnosed as having undergone radical resection of colorectal cancer;
• Patients who can read and communicate in Chinese.

Exclusion Criteria:

• Patients with multiple cancers;
• Patients who are unable to communicate due to dementia, language disorders or postoperative mental disorder or hearing impairment.

withdrawl Criteria：

• Patients with postoperative mechanical obstruction;
• Patients requiring reoperation for any indication prior to the initiation of formal evaluation of POGD.

516 cases needed to be included in the modeling group and 221 cases needed to be included in the validation group