Colon cancer is a malignant lesion of the colonic mucosa epithelium that occurs under the action of various carcinogenic factors such as environment or genetics. It is one of the common malignant tumors, with the highest incidence in the age group of 40-50 years old, accounting for 10%-15% of all malignant tumors. Colon cancer is a common malignant tumor of the gastrointestinal tract occurring in the colon area, mostly at the junction of rectum and sigmoid colon, with a male to female ratio of 2-3:1. The incidence rate is the third highest among gastrointestinal tumors. Colon cancer is mainly adenocarcinoma. Colon cancer can develop along the circumference of intestinal wall, spread up and down along the longitudinal path of intestinal tube or infiltrate deeply into the intestinal wall, and can be implanted into the abdominal cavity in addition to metastasis and local invasion through lymphatic vessels and blood stream.
Etiology
The main causes of colon cancer development are high-fat recipes and insufficient fiber intake. Chronic inflammation of the colon makes the incidence of bowel cancer higher than that of the general population. The incidence of colon cancer is five times higher in those with colon polyps than in those without colon polyps. Familial multiple intestinal polypomas have a higher incidence of cancer. Genetic factors may also be involved in the development of colon cancer.
Symptoms
There are no obvious symptoms in the early stage, and progressive stage may show stool changes, blood in stool, abdominal mass, anemia, abdominal pain, wasting or cachexia. The right hemicolectomy lumen is large, the stool is liquid-like, the cancer is mostly ulcerated or cauliflower-shaped, rarely forming a circular stricture, and obstruction does not often occur. If the carcinoma ulcerates and bleeds, secondary infection, accompanied by toxin absorption, fever appears. The lumen of the left hemicolectomy is thin and the stool is dry and hard. Left hemi-colon cancer is often infiltrative type, which easily causes annular stenosis and mainly manifests as acute and chronic intestinal obstruction.
Examination
1.Fiber colonoscopy and biopsy pathology
Colonoscopy can detect cancer, observe its size, location and local infiltration range, whether there is stenosis or whether the colonoscope can pass, and whether there is bleeding. It can also find out whether there are co-existing colon polyps and whether there are multiple colon cancer tumors.
2.CT and enhanced CT
The location of tumor can be observed from the image, and the possibility of lymph node metastasis can be inferred from the enlargement of lymph nodes. The relationship between the tumor and surrounding organs can be understood, and the possibility of resection can be inferred. It can understand the metastasis of liver, spleen, large omentum, adrenal gland and peritoneum, and determine the possibility of distant metastasis.
3.Barium enema
It can be seen that the intestinal wall at the site of cancer is stiff, poorly dilated, peristalsis is weakened or disappeared, the colonic pouch is irregular or disappeared, the intestinal lumen is narrowed, the mucosal folds are disordered, destroyed or disappeared, and the filling is defective, etc. Barium-air double contrast imaging is more helpful for the diagnosis of tumors with tissues in the colon. For progressive cancer, it can determine the location of the tumor and understand the situation of the adjacent intestinal segment, determine the scope of resection of the intestinal segment and whether it is necessary to free the nearby ligament or ligament, so as to make the anastomosis reconstruction convenient and tension-free and guarantee the smooth healing of the anastomosis.
4.Cancer embryonic antigen (CEA)
It has little diagnostic value for early tumor, but is helpful for speculating prognosis and judging recurrence, especially if it is higher before surgery and decreases significantly after surgery, and if it is persistently elevated in the subsequent review, it indicates recurrence or metastasis.
Treatment
The treatment of colon cancer is mainly surgery, supplemented by chemotherapy, targeted therapy, traditional Chinese medicine and other supportive treatments to improve the surgical resection rate, reduce the recurrence rate and increase the survival rate. The scope of resection varies depending on the location of the tumor.
1.Right hemicolectomy is applicable to cancer in cecum, ascending colon and hepatic flexure of colon.
2.Left hemicolectomy is applicable to cancer of descending colon and splenic flexure of colon.
3.Transverse colectomy is applicable to cancer of transverse colon.
4.Sigmoid colon cancer, in addition to resection of sigmoid colon, should also be part of descending colon resection or part of rectal resection, and add regional lymph node dissection.
5.For surgery with intestinal obstruction, if the patient’s condition allows, a stage of resection and anastomosis can be done. It is also possible to resect anastomosis + ileal prophylactic fistula, and to return the fistula in the second stage. If the patient’s condition is poor, colostomy can be performed first, and then second stage radical resection can be performed after the condition improves.
If the tumor is widely infiltrated or fixed with the surrounding tissues and organs and cannot be removed, the intestinal canal is obstructed or may be obstructed, short-circuit surgery can be performed and colostomy can also be performed. If distant organ metastasis and local tumor is still allowed to be resected, local palliative resection can be used to relieve obstruction, chronic blood loss, infection poisoning and other symptoms.
At present, the minimally invasive laparoscopic method for radical surgery of colon cancer has received good results, and this method has become a powerful tool for radical treatment of colon cancer, that is, it provides the operator with good vision and exposure, so that the whole process of surgery is under precise control, and the patient recovers quickly and with little pain.
Prognosis
Most of colon cancers can obtain satisfactory results after active surgical treatment, supplemented with regular chemotherapy after surgery.
Prevention
Patients with family history of tumor should have regular colonoscopy, and healthy people should be encouraged to have colonoscopy to detect benign colon masses and treat them endoscopically to avoid malignant transformation.