Colorectal cancer is one of the common malignant tumors of the gastrointestinal tract. In western economically developed countries, for every 25 babies born, 1 will later suffer from colorectal cancer. In China, the incidence of colorectal cancer has been increasing year by year in the past 20 years due to the influence of factors such as changing dietary habits. Chen Xueqing, director of the Department of Gastroenterology at the First Affiliated Hospital of Guangzhou Medical College, pointed out that Guangzhou has traditionally been the hardest hit by digestive tract diseases. In the past 10 years, the incidence of colorectal cancer in Guangzhou has increased for both men and women, by 44% and 32% respectively. The reason for this is that there are two reasons for the rising incidence of gastrointestinal tumors in Guangzhou and the surrounding areas. On the one hand, it stems from the traditional dietary habits of residents in Fujian and Guangdong, and the common pickled products, brine and fish sauce in the recipes are the reasons for the high incidence of gastrointestinal cancer; on the other hand, the absolute amount of high-fat, high-protein and low-fiber foods consumed by Guangzhou residents has increased significantly, and the fast-paced modern lifestyle has also contributed to the spread of cancer. What exactly causes colorectal cancer? Research shows that diet, environment, genetics and race are all related to the development of colorectal cancer. The dietary factors and environmental factors are more important. Take Japan as an example, in the 1950s, Japan, like China, was a country with a low incidence of colorectal cancer. As the economy recovered and developed after the war, the incidence and mortality rate of colorectal cancer in Japan also increased. According to the Japanese Cancer Society, from 1947 to 1978, the mortality rate of colorectal cancer increased approximately twofold, while various other cancers such as lung cancer only increased by 60%, and stomach cancer and cervical cancer decreased by 30% and 60%, respectively. — Colorectal cancer can somehow be said to be a disease of affluence. Analyzing its causes, firstly, it is caused by the increase of fat diet and decrease of fiber diet. The increase of colorectal cancer incidence in China’s cities in recent years is also related to the change of diet structure. Secondly, the relationship between environment and colorectal cancer is very close. Environmental factors include: lack of selenium in the soil; the influence of schistosomiasis, which is also a high incidence area of colorectal cancer in China; smoking can easily cause colorectal cancer. Thirdly, it is genetic factor. About 10% of colorectal cancer is related to genetic factors, so the offspring of patients diagnosed with familial colon polyposis, hereditary non-polyposis colorectal cancer and sporadic hereditary colorectal cancer should be closely tracked and followed up. Also, some benign tumors of the large intestine called polyps should not be ignored. People who have had ulcerative colitis for a long time also have a greater chance of developing colorectal cancer. In summary, people with one of the following conditions should be considered as a high-risk group for colorectal cancer: adults in areas with a high incidence of colorectal cancer, such as large cities and the southeast coast of China; patients with colorectal adenoma, family members with multiple familial adenomatosis; patients who have previously suffered from colorectal cancer; patients with schistosomiasis; family members of patients with colorectal cancer; members of cancer family syndrome; people who have received radiation therapy to the pelvis (some people It is believed that the chance of developing colorectal cancer is 10 times higher than that of normal people. What are the symptoms of colorectal cancer? The symptoms and clinical manifestations of colorectal cancer depend on the location of tumor growth, the size of the tumor and the early and late stage of the disease. We can roughly divide the colon into three parts, one is the right half colon, the second is the left half colon, and the third is the rectum. The right half of the colon has more water in the stool, and the stool is like fecal soup at this time. The rectum is about 1518 cm long, and the stool reaches the rectum, is close to forming, and stimulates the surrounding nerves and bowel muscle groups to produce bowel movements. Therefore, when colorectal cancer starts to grow and the cancer is less than 0.5 cm in diameter, it is almost asymptomatic no matter where it grows. However, as the tumor grows and invades the surrounding normal tissues, blood vessels and nerves, a series of symptoms will appear. Characteristics of right hemicolectomy The stool still appears as semi-flowing thin paste when it is in the right hemicolectomy, so it is not easy to show the bleeding symptoms caused by the stool rubbing against the cancer foci, which is often caused by the necrosis and detachment of the cancer foci, but due to the fine peristalsis of the cecum and ascending colon, the blood and the thin paste-like stool are evenly mixed, which is not easily detected by naked eyes. Due to the long-term chronic blood loss and the absence of obvious changes in stool habits, patients often seek medical attention for anemia. Some data showed that among 226 patients with right hemicolectasis, 58.8% of them had hematocrit below 10 grams. With the enlargement of the cancer, the abdominal mass can be felt in the right side of abdominal pain, which accounts for about 79.1% of the symptoms seen at the clinic. At the same time, tumor invasion of the intestinal wall can cause hidden pain, or even peri-enteritis, and the pain will gradually worsen. If paroxysmal abdominal pain occurs, it is often accompanied by obstruction symptoms, but the most common symptoms of right hemicolectomy are anemia, abdominal mass and abdominal pain, and barium enema angiography shows stiffness of the intestinal wall with filling defects. As stool passes from the right hemicolectomy to the left hemicolectomy, the stool gradually becomes solid due to water reabsorption, thus blood in the stool caused by stool friction is much more common in cases of left hemicolectomy than in cases of right hemicolectomy. Since the visible blood in the stool of left hemicolectomized colon cancer prompted patients to seek medical attention, the anemia caused by long-term chronic blood loss was less prominent than that of right hemicolectomized colon cancer patients. Similarly, in 226 patients with left hemicolectasis, only 38% of them had hematocrit less than 10 grams. Meanwhile, paroxysmal abdominal pain caused by intestinal obstruction is also more common in left-sided colon cancer than right-sided colon cancer, and some reports suggest that it is about 8 times more common. This is mainly due to the difficulty of passing through the cancer because of the dry and formed stool. Therefore, blood in stool and intestinal obstruction are the main manifestations of left-sided colon cancer. Features of rectal cancer Rectal cancer and sigmoid colon cancer account for more than 70% of patients with colorectal cancer, and rectal cancer accounts for more than half of all patients with colorectal cancer. Since the lesions are low, the main clinical manifestations are blood in stool and change in bowel habits. Blood in stool accounts for 90% of rectal cancer, mostly fresh blood and dark red blood, which is not mixed with stool, and is the oozing blood after tumor necrosis and shedding to form ulcer surface. Large amount of bleeding is rare. As the lesion stimulates the intestine, the number of stools increases, and the number of stools can be as many as 10 or 10 times a day. Therefore, rectal cancer is often misdiagnosed as chronic bacillary dysentery or hemorrhoids. If you have the above symptoms, you should first suspect whether you have colorectal cancer and go to hospital immediately, preferably to a specialist oncology hospital for further examination. With the development of the disease and the spread and metastasis of cancer to all parts of the body, some symptoms of advanced cancer can also appear. Advanced patients can show symptoms such as anemia, swelling, ascites, lump on the left clavicle, large liver and jaundice. For patients with early stage GI cancer, if they are detected and treated in time, the 5-year survival rate can be more than 90%, but for patients with advanced stage, the chance is less than 10%, so the concept of “early detection, early diagnosis and early treatment” has become an important means to prevent cancer and maintain GI health. However, many people have changed their faces when it comes to endoscopy and feel that gastroscopy and colonoscopy are very painful, but in fact, with the continuous improvement of endoscopy technology, endoscopy has become easy to perform nowadays. And compared with imaging, colonoscopy and gastroscopy can directly observe the morphology of the lesion, with a clear field of view, strong resolution and high accuracy of the biopsy rate.