Colorectal cancer

　　From the perspective of epidemiology, the incidence of colon cancer is related to genetics, environment, lifestyle, especially dietary habits.

　　1. Environmental factors:Research has shown that among various environmental factors, dietary factors are the most important, and there is a positive correlation between the incidence of colorectal cancer and the consumption of high-fat foods in the diet. In addition, it may also be related to the lack of trace elements and changes in lifestyle.

　　2. Genetic factors:If someone's first-degree relative, such as parents, has had colon cancer, their risk of developing the disease is 8 times higher than that of the general population. About 1/4 of new patients have a family history of colon cancer. Familial colon polyps are an autosomal dominant genetic disease, with an incidence rate of up to 50% in the family. If not treated, there is a possibility of developing colon cancer after the age of 10.

　　3. Colorectal adenoma:Autopsy material studies have found that the incidence of colorectal adenomas is basically consistent with colorectal cancer. According to statistics, the incidence of colorectal cancer in patients with a single adenoma is 5 times higher than that in patients without adenomas, and that in patients with multiple adenomas is twice as high. Villous adenoma-like polyps are prone to develop into cancer, with an incidence of about 25%, and the incidence of tubular adenoma-like polyps is 1-5%.

　　Common complications after colorectal cancer surgery mainly include anastomotic leakage, preliminary sacral hemorrhage, ureteral injury, stoma necrosis, and intra-abdominal hernia.

　　1. Anastomotic leakage:Anastomotic leakage is a serious complication of colorectal surgery, with a higher incidence in the one-stage operation of the left half colon and rectum. The following reasons for occurrence are analyzed: insufficient preoperative preparation; malnutrition in patients; surgical operation errors, such as excessive dissection of the intestinal tract ends and mesentery during the operation, or excessive resection of the fat tissue around the anastomosis of the colon, injury to the mesenteric blood vessels of the colon, poor blood supply of the anastomosis, excessive tension of the anastomosis, and insufficient suture tightness, all of which can affect the healing of the anastomosis.

　　2. Preliminary sacral hemorrhage:Preliminary sacral hemorrhage is a serious complication of rectal surgery, which is often fatal. The main reason is the injury to the sacral plexus during the separation of the posterior wall of the rectum. Since the sacral plexus is reticulated and fixed in front of the sacrum, and communicates with the vertebral veins in the small foramen of the sacrum, once the bleeding point retracts into the small foramen of the sacrum, it is difficult to stop the bleeding.

　　In addition, there are complications such as ureteral injury, stoma necrosis, and intra-abdominal hernia. All these complications are directly related to surgical procedures. The surgical methods for colorectal cancer are relatively mature, and each surgery has its important steps.

　　The earliest symptoms of colorectal cancer may include abdominal distension, discomfort, and dyspeptic-like symptoms, among which in the case of right half colon cancer, it is mostly abdominal pain or dull pain. The symptoms of early colorectal cancer may start as intermittent and then become persistent.

　　1. Abdominal mass:It is a mass infiltrated by the tumor or the omentum and surrounding tissues, with hard texture, irregular shape, and some can have a certain degree of mobility along the intestinal tract. In the late stage, the tumor infiltration is severe, and the mass can be fixed.

　　2. Intestinal obstruction manifestations:Incomplete or complete low intestinal obstruction symptoms, such as abdominal distension, abdominal pain, constipation, or constipation. Common symptoms of colorectal tumors are visible abdominal bulging, intestinal pattern, local tenderness, and hyperactive bowel sounds. The left half of the colon has a relatively narrow lumen, and the stool is already thick and formed here. Moreover, this part is mostly infiltrative cancer, with annular narrowing of the lumen, so intestinal obstruction symptoms appear earlier.

　　3. Intoxication symptoms:It is also one of the clinical manifestations of colorectal cancer. Due to the ulceration, bleeding, and absorption of toxins from the tumor of colorectal cancer, it is common for patients with colorectal cancer to present with symptoms such as anemia, low fever, fatigue, weight loss, and edema, among which anemia and weight loss are prominent. The right half of the colon has abundant blood supply and lymph, strong absorption capacity, and cancer masses are mostly soft, prone to ulceration, necrosis, and bleeding infection, so the main symptoms are intoxication.

　　4. Late-stage symptoms:Manifestations of distant metastasis, such as jaundice, ascites, edema, and signs of liver metastasis, as well as cachexia, rectal anterior凹 masses, and enlarged supraclavicular lymph nodes, and other manifestations of tumor spread.

　　The World Health Organization has proposed a sixteen-character guideline for the prevention of colorectal cancer, namely 'Reasonable diet, moderate exercise, quit smoking and limit alcohol, and maintain psychological balance.' Specific measures include the following aspects:

　　1. Regular check-ups:High-risk groups for colorectal cancer, such as men over 40, patients with familial multiple intestinal polyps, patients with ulcerative colitis, chronic schistosomiasis patients, and those with a family history of colorectal cancer, should have regular examinations, be vigilant about the signs and early symptoms of colorectal cancer, such as changes in defecation habits, alternating diarrhea and constipation, blood in feces or black stools, and the shape of feces becoming flat and thin.

　　2. Improve dietary habits:Change the habit of taking meat and high-protein foods as staple foods. Eat less high-fat foods, especially to control the intake of animal fats. Arrange daily diet reasonably, eat more fresh fruits and vegetables rich in carbohydrates and rough fibers, appropriately increase the proportion of coarse grains and mixed grains in staple foods, and not too fine or refined.

　　3. Prevent and treat intestinal diseases:Actively prevent various polyps, chronic enteritis (including ulcerative colitis), schistosomiasis, chronic dysentery, etc., and should be treated early for intestinal polyps. Colon polyps are divided into five categories, namely adenomatous polyps, inflammatory polyps, hamartomatous polyps, biochemical polyps, and mucosal hypertrophic exostoses, among which adenomatous polyps are true tumor polyps and are precancerous lesions of colon cancer. Therefore, when colon adenomas are found, they should be removed at the benign adenoma stage and pathological examination should be performed. If not treated early, the vast majority will become colorectal cancer.

　　The main methods for examining colon cancer are as follows:

　　1. X-ray examination:Including the whole digestive tract barium meal examination and barium enema examination. It can observe the full picture of the colon shape, whether there are multiple polyps and multiple cancer foci, and provide evidence for the surgical treatment of colon cancer patients.

　　2. Endoscopic examination:For those with hematochezia or changes in defecation habits, but no abnormalities found in rectal examination, routine fiberoptic colonoscopy should be performed. Not only can it find various types of lesions in the colon, but it can also take tissue biopsy for definite diagnosis, in order to avoid misdiagnosis or missed diagnosis.

　　3. Serum carcinoembryonic antigen (CEA) test:It is not specific for the detection and diagnosis of colon cancer. The value often increases with the growth of the tumor, and can recover to normal after the complete resection of colon tumor. It can increase several weeks before recurrence, so it is helpful for estimating the prognosis, monitoring the efficacy, and recurrence.

　　4. B-ultrasound scan, CT or MRI examination:None can directly diagnose colon cancer, but they have certain value in determining the location, size, and relationship with surrounding tissues of the tumor, as well as in the judgment of lymph node and liver metastasis. It is mainly suitable for understanding the degree of infiltration of the tumor into the intestinal tract and the presence or absence of local lymph nodes or distant organ metastasis.

　　5. Fecal examination:Through the detection of tumor M2 pyruvate kinase (M2-PK) in feces, it is found that the M2-PK value of colon cancer patients is 14 times that of normal people, so the detection of fecal tumor M2-PK provides a promising new method for colon cancer screening.

　　Colon cancer patients should arrange their daily diet reasonably, eat more fresh fruits and vegetables, and other foods rich in carbohydrates and rough fibers, appropriately increase the proportion of coarse grains and mixed grains in staple foods, and not too fine or refined.

　　Carcinogens produced by high-fat, high-protein, and low-fiber diets are numerous, and they act on the large intestine for a long time, which inevitably leads to an increase in the incidence of colorectal cancer. Therefore, eat less or no foods rich in saturated fat and cholesterol, including: lard, beef fat, fatty meat, animal internal organs, fish roe, etc.

　　Eat foods rich in unsaturated fatty acids in moderation, such as olive oil and tuna. Supplement dietary fiber of more than 35 grams per day. Eat more foods rich in dietary fiber: konjac, soybeans and their products, fresh vegetables and fruits, seaweed, etc. Use some coarse grains to replace fine grains. Eat more fresh vegetables and fruits to supplement carotene and vitamin C. Eat walnuts, peanuts, dairy products, seafood, etc. in moderation to supplement vitamin E. Pay attention to consuming foods rich in trace elements such as selenium, such as malt, fish, and mushrooms.

　　Patients with colorectal cancer should avoid spicy foods, such as chili and pepper, which have a stimulating effect on the anus and should not be eaten. Patients who have undergone colorectal cancer surgery should pay attention to strengthening nursing and diet nutrition after surgery to promote the recovery of the patient's body.

　　The principle of Western medicine in the treatment of colorectal cancer is comprehensive treatment with surgery as the main method, combined with chemotherapy, radiotherapy, etc. to reduce the recurrence rate after surgery and improve the survival rate. For inoperable colorectal cancer, neoadjuvant chemotherapy can be adopted, which can reduce the stage of the tumor on one hand, converting some inoperable tumors into operable tumors; on the other hand, it can extend the patient's survival time and improve the quality of life of the patient.

　　The scope of resection for radical colorectal cancer surgery includes the intestinal loop where the tumor is located and the entire mesocolon. That is, the tumor itself is removed, and the potential metastatic lymph nodes are completely cleared. Therefore, only a thorough operation can possibly cure colorectal cancer.

　　In addition, patients with liver and lung metastases have not completely lost the opportunity for treatment. The new view holds that if the metastatic lesions can be removed simultaneously, they should be removed together with the lesions of colorectal cancer. If the metastatic lesions cannot be removed, new adjuvant chemotherapy should be performed first to reduce the stage and then removed. In a part of the liver metastasis patients, the liver metastasis is limited to one lobe or segment, the operation is not only simple but also the 5-year survival rate can reach 50%. The choice of surgical indications and the experience of the surgeon are key factors in determining surgery.