Colorectal cancer: I: incidence The incidence rate ranks the fourth and fifth in the incidence rate of malignant tumors in China, accounting for 8.25%, and in the past decade, the incidence rate has an increasing trend; the incidence age is mostly 30-70 years old, accounting for 80%, patients under 30 years old account for 10-15%, male: female = 1.5-2.0:1; among all colorectal cancers, rectal and recto-b junction cancers account for 60-70%, followed by sigmoid colon Among all colorectal cancers, rectal and recto-b junction cancers account for 60-70%, followed by sigmoid colon, cecum, ascending colon, descending colon and transverse colon. Rectal cancer mainly occurs in the middle and lower rectum, accounting for about 70-80%. Multiple cancers are more common, accounting for about 5-8%, and can occur in different parts at the same time or successively; 2: Causes 1, dietary factors: high-fat and low-fiber diet increases bile acid and cholesterol metabolites in the intestine, increases anaerobic bacteria in the stool, which increases carcinogenic factors; lack of fiber in food reduces stool volume and slows down intestinal movement, which increases the concentration of carcinogens in the intestine and prolongs the contact time between carcinogens and colonic mucosa. A: familial polyadenomatosis is an autosomal dominant disease, involving all the large intestine and even the entire gastrointestinal tract, and if not treated, 100% of them will become malignant; among patients with colorectal cancer, 50% of them have two or more cancerous lesions. Gardner’s syndrome: familial polyadenomatosis with multiple skin epidermoid cysts and soft tissue tumors, multiple osteomas of the skull and mandible is called “Gardner’s syndrome”; Turcot’s syndrome: with malignant tumors of the central nervous system; B: cancer family syndrome: belongs to B: cancer family syndrome: an autosomal dominant disease with an ectopic rate of 90% (i.e., 90% of children can develop the disease); the age of onset of cancer is early, often multiple colorectal cancer; such patients have more chances of developing endometrial cancer, ovarian cancer and other organ cancers; C: the chance of death from colorectal cancer among family members of colorectal cancer patients is 4 times higher than that of the general population; D: inflammatory colorectal disease: patients with ulcerative colitis have a 5-10 times higher chance of developing colorectal cancer than normal people. D: inflammatory colorectal diseases: the chance of colorectal cancer in patients with ulcerative colitis is 5-10 times higher than that in normal people, the longer the disease period and the larger the lesion, the higher the risk of cancer, and the chance of colorectal cancer in patients with Crohn’s disease and schistosomiasis is also greater than that in normal people; E: colorectal adenoma: the risk of cancer in such patients increases, the larger the polyps, the greater the number, the worse the epithelial differentiation, the higher the chance of cancer. F: other relevant factors: previous colorectal cancer, pelvic radiation therapy, long-term exposure to synthetic fibers, dyes, rubber, certain micronutrient deficiencies (such as molybdenum, selenium, etc.); III: diagnosis Comprehensive medical history; different tumor sites, different symptoms. A: right hemicolectomy: often umbrella type or ulcerated type, protruding from the intestinal cavity, often accompanied by abdominal mass, anemia, intermittent blackening, weakness, wasting, etc.; B: left hemicolectomy: cancer often grows infiltratively, prone to circumferential stenosis, often causing abdominal pain, difficult stool, pus and blood stool, prone to intestinal obstruction; C: rectal cancer: often manifests as change in stool habit, pus and blood stool, urgency, anal pain, if the tumor invades the sacral plexus nerve. If the tumor invades the sacral plexus nerve, the sacrococcygeal area is often in severe pain. A: Rectal examination: 70% of rectal cancers can be detected by rectal examination; B: Fecal occult blood test: about 50% of positive fecal occult blood is caused by colorectal cancer, and the occult blood test should be repeated 3 times; C: Barium enema and sigmoidoscopy: suspected patients over 40 years old should be routinely examined. be done as routine examination, and fiber colonoscopy should be performed if necessary. If rectal cancer has been confirmed by rectal finger diagnosis and rectoscopy, full colonoscopy is still needed to exclude whether there are cancer foci in the proximal colon at the same time;; D: To determine the extent of lesions and metastasis, comprehensive examination of colorectal cancer patients should include: chest X-ray, liver function, liver ultrasound, abdominal CT, CEA measurement, rectal endoluminal ultrasound scan, IVP (for Low-grade cancer or those with urinary symptoms); IV: Pathology and metastatic modalities Colorectal cancer gross typing: augmentation, ulcerative, infiltrative, school-like. Histological typing: papillary adenocarcinoma, tubular adenocarcinoma, mucinous adenocarcinoma. The degree of differentiation: low malignancy (highly differentiated), moderate malignancy (moderately differentiated), high malignancy (poorly differentiated); Duke’s stage: established in 1935, according to the depth of cancer infiltration and the presence of lymph node metastasis, stage A: cancer confined to the intestinal wall; stage B: cancer penetrating the intestinal wall; stage C: lymph node metastasis; stage C1: cancer adjacent to lymph node metastasis; stage C2: mesenteric lymph node or mesenteric Stage D: distant metastasis; V. In 1978, China proposed the clinicopathological staging of colorectal cancer: Stage I: (equivalent to Dukes stage A), the cancer is confined to the intestinal wall and divided into three sub-stages Stage I0: the lesion is confined to the mucosal layer; Stage I1: the lesion invades the sub-mucosal layer; Stage I2: the lesion involves the muscular layer of the intestinal wall but does not penetrate the intestinal wall; Stage II: the lesion has penetrated the intestinal wall without lymph node metastasis; Stage III: the lesion has penetrated the intestinal wall without lymph node metastasis. Stage III: cancer has penetrated the intestinal wall and has lymph node metastasis; Stage III1: lymph node metastasis is limited to the vicinity of the cancer foci; Stage III2: lymph node metastasis in the lymph nodes and root lymph nodes of the lymph vessels; Stage IV: cancer cannot be resected or completely resected because of extensive infiltration, distant metastasis or implantation; V: prognosis The 5-year survival rate of colorectal cancer is 30-40%, which is the best prognosis among common malignant tumors. Colon cancer is better than rectal cancer; with radical resection, the 5-year survival rate can reach 55-70%, and some stage IV cases can still be palliative resection, which can prolong the survival time and improve the quality of life; if the primary foci are still early and there are single or several liver or lung metastases, the primary foci can be radically resected, and then the metastases can be locally or extensively resected; factors affecting the prognosis of colorectal cancer: disease duration, tumor site, disease stage, treatment level, immune status; VI. Sixth: direct infiltration of colorectal cancer metastasis: implantation: lymphatic metastasis: hematogenous metastasis: it is an important way of colorectal cancer dissemination, often invading veins, with a chance of up to 20-30%, especially in rectal cancer; Seventh: treatment surgery is the main means: according to different parts of the tumor, choose different surgical styles; preoperative intestinal preparation: oral intestinal non-absorbable antibiotics, cleansing and enema; choice of surgical style: the intestinal tract should be prepared for surgery. enema; choice of operation: Ⅰ: cecum, ascending colon cancer: right hemicolectomy, including terminal ileum 10-15 cm; Ⅱ: hepatic flexure, splenic flexure and transverse colon: resection of transverse colon, part of ascending colon, part of descending colon; Ⅲ: descending colon and sigmoid colon cancer: resection from splenic flexure to sigmoid colon, proximal rectum and its mesentery and lymph nodes; Ⅳ: rectum: below 7 cm, Miles 7-10 cm. Dixon higher than 10 cm, anterior resection; V: colon cancer with intestinal obstruction: current right colon – one-stage resection anastomosis; left colon – controversial; mid-upper rectum – Hartman surgery; adjuvant therapy: Ⅰ: chemotherapy: advanced tumor, post-surgical recurrence and metastatic patients should be chemotherapy, commonly used 5-fu, FT207,UFT, mitomycin, etc.. Combination chemotherapy is better. Postoperative chemotherapy for colorectal cancer has no definite conclusion so far, but for those with lymph node metastasis, postoperative chemotherapy may be beneficial; Ⅱ: radiotherapy: preoperative radiotherapy can shrink rectal cancer and reduce local recurrence rate; postoperative radiotherapy can reduce or delay local recurrence; radiotherapy can also relieve presacral pain, but has no obvious effect on pain relief for colon cancer; VIII: recurrence and metastasis after surgery 40-70% of patients after radical resection Local recurrence and distant metastasis occur. The biological behavior of colorectal cancer is relatively good, and with the progress of surgery, radiation and drugs, some patients with recurrence and metastasis can still obtain long-term survival, and most patients have prolonged survival time; 70% of recurrence cases of colorectal cancer occur within 2 years after surgery, and 6% of recurrence over 5 years. It is found that 80-90% of patients with local recurrence die within 3 years; local recurrence is recurrence within the original surgical field, including: anastomosis, intrapelvic, perineal and abdominal wall incision recurrence, the most visceral metastasis is liver, followed by lung, bone, ovary and brain; the role of CEA: treatment of patients with recurrent metastasis: research shows that 20% of patients with recurrent rectal cancer until death have recurrent foci limited to If early diagnosis and active treatment can be made, better treatment results can still be obtained; 40% of patients can survive for 5 years after resection of isolated liver metastases; IX: progress of rectal cancer with total mesenteric resection; abolish the 5 cm rule and agree with the 3 cm rule; study of 3000 resected rectal cancer specimens: only 2.3% have lymphatic metastases at the distal 1 to 2 cm of the lesion. The rectum can be elongated by 3-5 cm after bilateral lateral ligament severance; the application of anastomosis; new procedures: Parks: transabdominal resection of the rectum and colon-anal tube anastomosis through the anal canal; Oskar: transabdominal free cut, distal resection through the anal flap, proximal pull-out anastomosis; Shafik: transabdominal free, circumferential incision at the edge of the anal skin crease, dissecting out the lower edge of the internal and external dilator muscle Shafik: transabdominal free, circumferential incision at the edge of the anal skin crease, dissecting out the lower edge of the internal and external sphincter, separating upward between the internal and external sphincter straight to the abdominal pelvic separation site of rendezvous, proximal colon pulled down and resected, and sutured with the perianal skin; anal preservation surgery for low to medium rectal cancer: 26% in the 1950s, 93% in the 1980s, common complications of anal preservation surgery: intestinal necrosis, leakage, stricture, obstruction, intestinal retraction, infection; 150 cases of anastomotic anal preservation surgery in China: the survival rates of 1-4 years were 94%, 84%, 76% and 63%, respectively 84%, 76%, 63%, similar to Miles surgery at the same stage of disease; X: recurrence adjuvant examinations: 65% recurrence within 2 years, follow up for at least 2 years; regular measurement of CEA; pelvic X-ray, sometimes visible soft tissue shadow; pelvic B-ultrasound; CT examination: can show a 1 cm diameter mass.