As the age structure of our population is aging, the number of elderly patients is gradually increasing, so the treatment of elderly patients is becoming more and more important. With the increase of age, the function and structural state of various organs in the whole body are in progressive decline, gradually entering the compensated or decompensated state, the reserve capacity and immune function of the body are low, and the response to disease, infection, trauma and other stressful situations is slow, and there are many coexisting diseases, which often manifest in the perioperative period as rapid progress of lesions, many postoperative complications, easy deterioration and high morbidity and mortality rate. 1.1 Clinical data 1.2 General data 63 cases of elderly colon and rectal cancer surgery patients over 65 years old with complete data were collected between 1997 and 2000. There were 29 male cases and 34 female cases. 30 cases were aged 65-69 years, 26 cases were aged 70-79 years, and 7 cases were aged 80 years or above. There were 40 cases of colon cancer and 23 cases of rectal cancer. 1 case of Dukes stage A0, 1 case of stage A1, 4 cases of stage A2, 22 cases of stage B, 13 cases of stage C1, 6 cases of stage C2, and 16 cases of stage D. 1.3 Treatment All 63 cases in this group were treated with surgery. There were 14 cases of emergency surgery, 49 cases of elective surgery, 16 cases of intraoperative placement of portal vein or laparoscopic pump, 8 cases of combined organ resection, including 5 cases of partial hepatectomy, 1 case of cholecystectomy, 1 case of partial resection of the descending muscular layer of duodenum and 1 case of partial vagotomy. 1.5 Results There were 36 cases with different degrees of postoperative complications in this group, accounting for 55.6% of the total number of cases in the group. The complications were shown in Table 3. 4 cases died after surgery (within 1 month after surgery, including 2 cases of emergency surgery and 2 cases of elective surgery), with a mortality rate of 6.3%. Among them, 1 case died of MSOF, 1 case died of myocardial infarction, and 2 cases died of ARDS. 2, Discussion Elderly patients with colon and rectal cancer are mostly in advanced stage when they are diagnosed, and most of them have developed to different degrees of intestinal obstruction, with 36 cases in this group and only 6 cases in stage A. The number of coexisting diseases and their severity is another characteristic of this group of patients, which is as high as 61.9% in this group. The most common diseases were mainly coronary heart disease, hypertension, chronic bronchitis, emphysema, pulmonary infection, hypoproteinemia, urinary system diseases, and diabetes mellitus. Thus, the postoperative survival rate is not only related to the type and stage of the tumor, but also closely related to the choice of surgical approach and the effectiveness of the prevention and treatment of coexisting diseases in the perioperative period. The choice of surgical treatment plan should be based on the patient’s condition, comprehensive estimation of the necessity and risk of surgery, solving the main conflicts, prolonging life and improving quality of life, shortening the operation time as much as possible, and using new technologies and materials such as anastomosis. At the same time, radical surgery must not be abandoned because of advanced age and coexisting diseases. Perioperative management can make a significant number of patients who were not able to tolerate radical surgery tolerate radical surgery [1]. With timely and reasonable prevention and treatment of coexisting disease, it is possible to improve the chance of radical surgery, which reached 65% (41 cases) in our group. To improve the postoperative survival rate, the key lies in the treatment of coexisting diseases and postoperative complications during the perioperative period. Cardiovascular disease is one of the most common coexisting diseases. For these patients, we should shorten the operation time as much as possible, reduce injury, avoid blood pressure fluctuation, and ensure myocardial oxygen and blood supply. Intraoperative and postoperative monitoring of ECG, blood pressure, blood oxygen, urine volume, central venous pressure, etc. should be closely monitored, and timely management should be made according to changes in the condition. There were 14 patients with coexisting hypertensive disease in this group, including 5 cases of class I, 4 cases of class II and 5 cases of class III. All of them used antihypertensive drugs before surgery, generally to about 18.7/12 kpa, and the antihypertensive drugs were used until the morning of the surgery, especially for patients with grade I coexisting cardiovascular and cerebrovascular damage, diabetes mellitus, and grade II and III patients. For cases where the preoperative blood pressure lowering does not reach the target, the following principles should be followed: (1) elective surgery, blood pressure >24/14.7kpa, postpone surgery (2) after treatment in the ward, it is close to the expected level, but the morning of the operation day to the operating room >24/14.7kpa <26.7/14.7kpa without cerebral cardiovascular symptoms, generally can be injected with a small amount of rapid-acting antihypertensive drugs, and wait for the blood pressure to fall to a level close to normal before The surgery can be started. (3) Emergency surgery with blood pressure >24/14.7kpa If the risk to the patient from delayed surgery exceeds that of hypertension, surgery is performed under close monitoring, applying antihypertensive drugs to maintain blood pressure at about 18.7/12kpa, avoiding dramatic fluctuations in blood pressure, and continuing to monitor blood pressure with antihypertensive drugs after surgery. There was no case of cerebral infarction, cerebral hemorrhage or other serious postoperative complications in this group. Patients with combined coronary artery disease are highly susceptible to acute myocardial infarction, severe arrhythmias and heart failure during the perioperative period, and the operative mortality rate is significantly higher than that of general patients. Myocardial infarction usually occurs within 1 week after surgery, especially within 3 days after surgery, so the main points of postoperative treatment are to prevent the imbalance between myocardial oxygen supply and oxygen demand, to give sufficient oxygen, and to correct water-electrolyte disorders, especially hypokalemia. One case in this group had symptoms of transient precordial discomfort and chest tightness half a month before surgery, ECG: ischemic ST-T changes, and myocardial infarction appeared one week after surgery, which led to death, and the lesson was profound. Since the symptoms of postoperative infarction are often not obvious, about 21%-37% are painless type, when unexplained hypotension, dyspnea, cyanosis, arrhythmia or signs of heart failure suddenly occur, all of them should be taken seriously, and ECG and myocardial enzyme spectrum and other examinations should be made immediately so as to make correct diagnosis and treatment in time. Drugs for coronary artery disease, such as ß-blockers, calcium antagonists and nitrates, should be used routinely until the morning of surgery to prevent imbalance of myocardial oxygen supply and consumption due to sudden discontinuation of the drugs. Aspirin and disulfiram should be discontinued 7-10 days before surgery to prevent increased postoperative bleeding [2]. Patients with heart failure should, in principle, be operated only after 3-4 weeks of heart failure control, but in patients with acute intestinal obstruction, the degree of heart failure should be weighed against the urgency of surgery, and surgery should be performed after active control of heart failure if the condition permits. In patients without intestinal obstruction, heart failure should be controlled first. Angiotensin-converting enzyme inhibitors (ACEI), diuretics, digitalis, etc. should be stopped 12 hours before surgery, and intravenous administration of drugs such as cetiran, dobutamine, dobutamine, etc. should be used. In this group, there were two cases of preoperative coexisting heart failure, one of which was sigmoid colon cancer causing cecum perforation and total peritonitis, which was treated briefly and operated urgently, and died of MSOF after surgery. the other case was treated preoperatively for nearly 3 weeks, and interventional chemotherapy was given once, and no serious complications occurred after surgery. The postoperative pulmonary complications such as pulmonary atelectasis, pulmonary infection, asthma, etc. are significantly increased and ARDS may occur in severe cases due to poor thoracic elasticity, weak respiratory muscle contraction, thinning of alveolar wall and reduced lung capacity and lung volume in elderly patients. ensure the supply of oxygen, use antibiotics and hormones, and use ventilator mechanical ventilation as soon as respiratory failure occurs. In this group, there were 15 cases of postoperative pulmonary complications, and 2 of them died of ARDS. Diabetes is a common coexisting disease in elderly patients, and there were 7 cases in this group, including 5 cases of type I diabetes and 2 cases of type II diabetes. It is especially easy to miss the diagnosis of occult diabetes. One patient in this group had severe hyperglycemia after surgery although fasting glucose was normal before surgery. Thus, any (1) with symptoms of diabetes mellitus, fasting blood glucose ≥ 7.84 mmol/L or random blood glucose ≥ 11.2 mmol/L (2) with or without symptoms of diabetes mellitus, repeated fasting blood glucose ≥ 7.84 mmol/L (3) with or without symptoms of diabetes mellitus, 1-hour and 2-hour blood glucose ≥ 11.2 mmol/L after oral administration of 75 g glucose should be considered as diabetes mellitus [3]. For type II diabetes mellitus, oral hypoglycemic drugs should be discontinued 2~3 days before surgery and replaced by insulin therapy.The dosage of insulin and route of administration should also be adjusted according to the needs of the condition before surgery for type I diabetes mellitus to control blood glucose and urine sugar to the ideal level: about 7.2~8.9mmol/L for blood glucose and +~- for urine sugar. And the blood glucose is constantly monitored during and after the operation, insulin is continued, and the ratio of glucose to insulin is constantly adjusted so that the blood glucose level is controlled to about 6.7~11.2mmol/L and urine sugar (+). For emergency surgery, there should be several hours of preparation, first enter isotonic saline, and adjust the insulin dosage according to the measured blood glucose results. At the same time, in order to prevent ketoacidosis, potassium, phosphorus and acidosis should be corrected in a timely manner. There was no case of ketoacidosis in this group. For patients with hypoproteinemia, exogenous human albumin should be supplemented in a timely manner after surgery to prevent the occurrence of anastomotic fistula. One patient in this group had a preoperative liver function Child grade C, which was not supplemented in time after surgery due to financial reasons, resulting in the occurrence of anastomotic fistula. The use of perioperative antibiotics should follow the principles of broad-spectrum, high-efficiency, and short-term. For elective surgery, they should be started 30 minutes before surgery and generally used for 3 to 5 days after surgery to avoid long-term abuse. However, for patients with coexisting pulmonary or other site infections and diabetes mellitus, it can be extended appropriately. sedman [4] et al. concluded that the rate of perioperative infections in general surgery patients is about 10%, and in our group, it was as high as 38% with 24 cases, and the sites of infection included respiratory system, urinary system, abdominal cavity, and incision, etc. Considering that our group were all contaminated surgeries and associated with frail immune function in old age, and also combined with diabetes mellitus, etc.