Colon cancer is a common malignant tumor of the digestive tract. Its main symptoms include abdominal distension, indigestion, changes in bowel habits, mucus, mucus, pus and blood, etc. Routine examinations include colonoscopy, abdominal plain films, barium enema, etc. The main treatment method is surgery. Mainly, supplemented by chemotherapy, immunotherapy, traditional Chinese medicine and other comprehensive treatments.
Disease overviewColon cancer refers to a malignant lesion of the colon mucosal epithelium that occurs under the influence of various carcinogenic factors such as environmental or genetic factors. It is one of the common malignant tumors, with the highest incidence rate in the 40- to 50-year-old age group. There are approximately 800 new cases worldwide every year. million, accounting for 10% to 15% of all malignant tumors.
PathophysiologyThe gross macroscopic classification of colon cancer can be divided into:
There are three types: mass type (cauliflower type, soft cancer), invasive type (constriction type, hard cancer) and ulcer type. Among them, the ulcer type is the most common, which is prone to bleeding, infection, and penetration in the left colon. The intestinal wall metastasizes earlier.
Histological types include:
1. Adenocarcinoma: accounts for about three-quarters.
2. Mucinous carcinoma: poorly differentiated and has a worse prognosis than adenocarcinoma.
3. Undifferentiated cancer: Very poorly differentiated and has the worst prognosis.
Clinical stages include:
Dukes stage A: the cancer is limited to the intestinal wall; Dukes stage B: the cancer has invaded outside the intestinal wall; Dukes stage C: accompanied by lymph gland metastasis; Dukes stage D: distant metastasis or extensive invasion into nearby organs. resection.
Ways colon cancer metastasizes include:
1. Direct invasion: Generally, it invades in a circular shape along the transverse axis of the intestinal tube, develops into the deep layers of the intestinal wall, and spreads slowly up and down along the longitudinal axis. After the cancer invades the serosa, it often adheres to surrounding tissues, adjacent organs, and the peritoneum.
2. Lymphatic metastasis: It is the main mode of metastasis of colon cancer. It usually spreads from near to far, but there is also non-sequential metastasis across borders. The probability of lymphatic metastasis increases after the cancer invades the muscular layer of the intestinal wall, such as the invasion of subserosal lymphatic vessels. , the chance of lymphatic metastasis is greater.
3. Hematogenous metastasis: Generally, cancer cells or cancer emboli first reach the liver along the portal vein system, and then travel to other tissues and organs such as the lungs, brain, and bones.
4. Abdominal implantation and metastasis: Cancer cells fall off in the intestinal cavity and can be implanted on the mucosa elsewhere; cancer cells that fall off in the abdominal cavity can be implanted on the peritoneum.
PathogenesisData from various places show that with the improvement of people's living standards and changes in dietary structure, the incidence rate has been increasing year by year. Although the exact pathogenesis of colorectal cancer has not yet been fully elucidated, further research on the pathogenesis of tumors has enabled people to change from the past single disease.
The theories of physical carcinogenesis, chemical carcinogenesis, viral carcinogenesis and mutational carcinogenesis have risen to multi-step and multi-factor comprehensive carcinogenesis theories. At present, people have gradually accepted this view, that is, the occurrence of colorectal cancer is a gradual process involving multiple oncogenes. Activation of tumor suppressor genes and inactivation of tumor suppressor genes. From an epidemiological point of view, the onset of colon cancer is related to heredity, environment, living habits, and especially diet.
1. Environmental factors: Research has proven that among various environmental factors, dietary factors are the most important. The incidence of colorectal cancer is positively related to the high fat consumption in food. In addition, it may also be related to the lack of trace elements and poor living conditions. Related to habit change.
2. Genetic factors: If a person's first-degree relatives, such as parents, have had colon cancer, their risk of contracting the disease is eight times higher than that of ordinary people. About 1/4 of newly diagnosed patients have a family history of colon cancer. Familial colon cancer Polyposis is an autosomal dominant genetic disease, and the prevalence in families can reach 50%. If left untreated, everyone may develop colon cancer after the age of 10.
3. Colorectal adenoma: Research on autopsy materials found that the incidence of colorectal adenoma is basically the same as that of colorectal cancer. According to statistics, the incidence of colorectal cancer in patients with a single adenoma is five times higher than that in patients without adenoma. The rate is twice as high as that of patients with a single adenoma. Villous adenomatous polyps are prone to develop into cancer, with a malignant transformation rate of approximately 25%, and tubular adenomatous polyps with a malignant transformation rate of 1-5%.
4. Chronic large intestine inflammation: It is reported that the prevalence of intestinal cancer is positively correlated with the endemic areas of schistosomiasis. It is generally believed that inflammatory changes in the intestines due to schistosomiasis may lead to canceration. Other chronic inflammations of the intestines may also lead to canceration. Possibly, patients with Crohn's disease or ulcerative colitis are 30 times more likely to develop colon cancer.
Clinical manifestations of colon cancer1. Early symptoms: In the earliest stage, there may be abdominal distension, discomfort, and indigestion-like symptoms. Among them, when it comes to right colon cancer, it is mostly abdominal pain or dull pain. Symptoms of early colon cancer may be intermittent at first and then become persistent. Changes in bowel habits are also one of the symptoms of early colon cancer. When right colon cancer occurs, early stools are thin, with pus and blood, and the frequency of bowel movements increases. When colon cancer continues to grow, it affects the passage of stool. Diarrhea and constipation may also occur alternately, while left colon cancer often presents with difficulty defecation, which will continue to worsen as the disease progresses.
2. Abdominal mass: It is a tumor or a mass infiltrated with the omentum and surrounding tissues. It is hard and irregular in shape. Some can have a certain degree of mobility with the intestinal tube. In the late stage, the tumor infiltration is serious and the mass can be fixed.
3. Intestinal obstruction symptoms: Symptoms of incomplete or complete low intestinal obstruction, such as abdominal distension, abdominal pain, constipation or constipation. Common symptoms of colon tumors are abdominal distension, intestinal type, local tenderness, and audible and hyperplasia on physical examination. Bowel sounds. The intestinal lumen of the left colon is relatively narrow, and the feces has become sticky and formed by now. Moreover, this part is mostly invasive cancer, and the intestinal lumen is circularly narrow, so symptoms of intestinal obstruction appear earlier.
4. Symptoms of poisoning: It is also one of the clinical manifestations of colon cancer. Due to the blood loss and toxin absorption of colon cancer tumors, colon cancer patients often suffer from anemia, low fever, fatigue, weight loss, edema and other symptoms, especially anemia, Weight loss is the main symptom. The right colon has rich blood supply and lymph, and strong absorptive capacity. The cancers are mostly soft cancers, which are prone to ulceration, necrosis, bleeding and infection, so poisoning symptoms are the main symptoms.
5. Late symptoms: There are signs of liver metastasis such as jaundice, ascites, and edema, as well as cachexia, anterior rectal concave mass, supraclavicular lymph node enlargement, and other manifestations of distant tumor spread and metastasis.