1. Development of sexual tumors The tumors of gastrointestinal tract we talk about here mainly refer to malignant tumors of stomach and large intestine, i.e. cancer. As we all know, the tumors found in the gastrointestinal tract are partly benign. Benign tumors are not easy to recur after removal and are less harmful to the organism, so we don’t talk much about them. Haiyan Ge, Department of Gastroenterology and Anorectal Surgery, Shanghai Oriental Hospital As we all know, stomach cancer is one of the cancers with the highest incidence worldwide. According to the statistics of the World Health Organization Cancer Control Program, as many as 7 million patients die from cancer every year worldwide, among which 700,000 patients die from stomach cancer. Globally, stomach cancer is the second most prevalent cancer among men and the fourth most prevalent among women, and East Asian countries (Japan, Korea, South Korea, and China) are the regions with high incidence of stomach cancer. Stomach cancer is the second most common tumor in China, with a prevalence age of 50 years or older, with 460,000 new cases and 450,000 deaths per year. According to the World Health Organization, China accounted for 47% of the world’s gastric cancer patients in 2010. Colorectal cancer is one of the most common malignant tumors in the world, and its incidence rate ranks second among malignant tumors in developed countries in Europe and America. In the past, the incidence rate of colon cancer in China was generally around the fifth or sixth place, but from the epidemic trend in recent years, with the change of people’s lifestyle and diet structure, the incidence rate of colon cancer in China is also on an obvious rising trend, about 20 cases per 100,000 people in general, and more than 40 cases per 100,000 people in Shanghai. The incidence of rectal cancer occupies the second place among cancers of the gastrointestinal tract. The characteristics of rectal cancer in China are: firstly, high incidence of lower and middle section; secondly, high incidence of young people; thirdly, 5-year survival rate after radical resection is about 60%, and 5-year survival rate after early cancer is 80%-90%. 2. Structure and function of gastrointestinal tract The gastrointestinal tract is a whole, but each has its own division of labor and influences each other. The stomach is the organ for storing and digesting food. The stomach is connected to the esophagus and the duodenum. The stomach has three main functions: it is a container for food after swallowing; it secretes digestive enzymes such as gastric acid and pepsin; and it grinds food so that solid food is ground up, made fine, and mixed thoroughly with gastric juice to become a paste-like surimi for easy absorption in the small intestine. The small intestine is about 3 to 5 meters long and is mainly responsible for absorbing nutrients. The specific process is: in the first step, under the action of bile and pancreatic juice digestive enzymes, three chemical changes occur in the paste-like chyme delivered from the stomach, namely, the conversion of starch into glucose and fructose, the conversion of protein into amino acids, and the conversion of fat into triglycerides and fatty acids; the second step is the absorption of water, electrolytes, sugars, amino acids, fatty acids, vitamins, iron and trace elements, etc. The Y-intestine is the section of the large intestine from the cecum to the rectum, which is about 1.5 meters long in normal adults, and its function is to absorb water and salt and form and transport feces. The rectum is the last part of the large intestine, which is connected to the anus, and its function is to store feces. When the feces in the rectum accumulates to a certain level it will send a notification to the brain and the person will expel feces. 3. Influencing factors of tract malignant tumor Below I would like to introduce five influencing factors that affect human to develop gastrointestinal tract malignant tumor. The first is the congenital genetic factor. For example, if a blood relative has suffered from stomach cancer, the incidence of stomach cancer in this group is four times higher than in the control group. Genetic susceptibility is an even more important factor in the development of colon cancer, such as familial intestinal polyposis, which is a recognized familial disease. An adult with familial intestinal polyposis will have cancerous polyps sooner or later with increasing age. Hereditary non-polyposis colon cancer is also a kind of colon cancer with genetic factors. These people have mutations in mismatch repair genes and are prone to colon cancer. The second is dietary factors. People with the following dietary habits are prone to stomach cancer: long-term consumption of fumigated and salted foods, high content of carcinogens such as nitrite, fungal toxins and polycyclic aromatic hydrocarbon compounds in foods; lack of fresh vegetables and fruits in recipes. People who are addicted to excessive animal fat and animal protein diet and lack of fresh vegetables and fiber-rich foods are prone to colon cancer. At the same time, moldy cereals contain a variety of fungal toxins, frequent consumption of moldy cereals, also prone to gastrointestinal cancer. For example, aflatoxin in cereals not only strongly causes liver cancer, but also may cause gastrointestinal cancer. The third is environmental factors. Environmental pollution has an important influence on the development of tumor: air pollution, automobile exhaust, industrial waste gas, waste water, waste residue contain a lot of carcinogenic substances; water pollution, heavy metal pollution will affect human drinking water sources and land, and then contaminate vegetables, fruits, food and drinking water. These are all factors influencing the development of gastrointestinal malignant tumors. In recent years, some cancer villages or areas with high incidence of cancer have been reported one after another, and a common feature is that they have a great relationship with serious environmental pollution. The fourth is bad habits and habits. For example, the incidence of stomach cancer is 50% higher in smokers than non-smokers, while the lack of moderate physical activity is related to colon cancer, and the addiction to smoked and baked foods may lead to the intake of carcinogens such as benzpyr, and the addiction to cured fish and meat may be harmed by nitrosamine salts and bacterial botulinum toxin. Lastly, gastrointestinal disease is a factor. Gastric polyps, chronic atrophic gastritis, residual stomach after partial gastrectomy and huge benign ulcers are precancerous lesions, which lead to cancer along the following pathways: chronic inflammation → intestinal epithelial hyperplasia of gastric mucosa → atypical hyperplasia (mild, moderate or severe) → cancer. Meanwhile, familial intestinal polyposis is a recognized precancerous lesion, and colonic adenoma, ulcerative colitis, and colonic schistosome granuloma, are closely associated with the development of colon cancer. Familial intestinal polyposis, rectal adenoma, especially choroidal adenoma may trigger rectal cancer. 4.Symptoms of intestinal malignant tumor Stomach cancer. Early gastric cancer mostly has no obvious symptoms, and a few people may have nausea, vomiting and upper gastrointestinal symptoms similar to ulcer disease. Therefore, the diagnosis rate of early gastric cancer is very low. Upper abdominal pain, loss of appetite and weight loss are the most common symptoms of progressive gastric cancer. Colon cancer has four symptoms: firstly, change in bowel habit and stool characteristics is often the earliest symptom, manifested as increased frequency of bowel movement, diarrhea, constipation, or alternating diarrhea and constipation, and blood, pus or mucus in stool; secondly, abdominal pain is one of the early symptoms, often persistent and hidden pain with uncertain location, or only abdominal discomfort or bloating; thirdly, there is an abdominal mass, mostly the tumor Thirdly, there is an abdominal mass, which is mostly the tumor itself, sometimes it may be a fecal mass in the intestinal cavity near the obstruction; finally, there is the symptom of intestinal obstruction, which is mostly the advanced symptom of colon cancer, caused by the narrowing of intestinal cavity or blockage of intestinal cavity due to the tumor. In the early stage of rectal cancer, there is no obvious symptom, and the following symptoms will appear only when the cancer breaks down and forms ulcer or infection: firstly, rectal irritation symptom, which is manifested as frequent bowel movement, change of defecation habit, feeling of anal drop, feeling of incomplete defecation, and feeling of urgency; secondly, intestinal lumen narrowing symptom, which is manifested as thin stool, deformation, and groove on the surface of cylindrical stool, until it is difficult to defecate; thirdly, cancer breaks down and infection symptom, which is manifested as blood and mucus on the surface of stool, and pus on the surface of stool. The third symptom is that the cancer is infected and the stool surface is bloody with mucus, and pus-blood stool appears. Therefore, we should attach great importance to blood in the stool and not easily think that it is bleeding from hemorrhoids, especially if you have a history of hemorrhoids in the past. If the bleeding worsens or does not heal repeatedly, it is important to seek prompt medical attention. The medical examination after the appearance of symptoms. 5, the hospital commonly used five major types of examination means First, endoscopy. Endoscopy is a hose equipped with a light source, it can enter the stomach through the mouth or enter the body through other natural orifices, the use of endoscopy can directly observe a variety of lesions on the mucosal surface of the gastrointestinal tract, which is a means of examination that can not be replaced by other methods of impactological examination. Endoscopy is also divided into several kinds. 1.Gastroscopy is the best means to discover gastric tumor. For lesions such as gastric mucosal erosion, ulcer and mass, biopsy can be taken to make pathological diagnosis. Modern gastroscopy technology is also able to perform gastroscopic resection of microscopic tumors and intra-mucosal cancer, which can really achieve the purpose of minimally invasive treatment. 2.Colonoscopy is the best means to discover colon tumors. Under colonoscopy, various lesions such as congestion, erosion, ulcers, polyps and masses on the surface of the intestinal wall can be clearly seen, and biopsies can be performed on the lesions, and small polyps and tumors can be removed under the microscope. 3. Proctoscopy (anoscope) is the most convenient means of examining rectal lesions. The length of the proctoscope is 10 cm, and it can clearly see the mucosal surface lesions of the middle and lower rectum. Another advantage of proctoscopy is that no bowel preparation is required prior to the examination, making it easy to apply in outpatient or physical examinations. 4, capsule endoscopy, also known as “medical wireless endoscopy”, is a new technology for the examination of gastrointestinal diseases that has emerged in recent years. The basic principle of capsule endoscopy is through a built-in camera and signal transmission device intelligent capsule, with the peristaltic movement of the gastrointestinal tract so that the capsule in the gastrointestinal tract movement and take images, the doctor use the external imaging workstation to understand the patient’s gastrointestinal tract situation, so as to make a diagnosis of the disease. Capsule endoscopy has the advantages of no trauma, no wires, no pain, no cross-infection, and does not affect the normal work of the patient. It overcomes the defects of traditional insertion endoscopy such as poor tolerance, not suitable for old and weak and critically ill patients, and is the preferred method for diagnosis of small intestinal diseases. The disadvantage is that it is difficult to see the whole picture of the large internal cavity (stomach), and it is not suitable if the small intestine is narrowed or obstructed (difficult to discharge the capsule). 5.Electronic small intestine microscopy (known as double balloon electronic small intestine microscopy) is an emerging technology of small intestine endoscopy in recent years, which can reach the middle and lower ileum and even the terminal ileum by adding an outer tube and an airbag at the top of the original propulsion type small intestine microscope. Electronic small bowel microscopy has the advantages of wide field of view, clear images, and the feasibility of endoscopic biopsy and related treatment. If the combination of radial and transanal approaches is used, it is possible to obtain a comprehensive and thorough examination of the entire small intestine. However, due to the thin diameter of the electronic small intestine microscope, the small intestine is very long and folded and coiled in the abdominal cavity, complications such as intestinal mucosal injury, perforation and bleeding, postoperative abdominal pain and abdominal distension may occur during the examination. Recent clinical practice has proved that for people with high incidence of gastrointestinal tumors (such as those with genetic factors and history of gastrointestinal polyps), they should undergo regular endoscopy to exclude the possibility of cancer, even if they have no preexisting symptoms. According to foreign research data, for middle-aged and elderly people with gastrointestinal tumor development factors, regular gastroscopy or colonoscopy and timely removal of gastrointestinal polyps found during the screening can also reduce the incidence and mortality of gastrointestinal malignant tumors. Second, fecal occult blood test. It is the most widely used and evaluated test in gastrointestinal tumor screening today, and has the significant advantages of being fast, simple, painless, and easy to be repeatedly applied. For a patient with repeated positive fecal occult blood tests, regardless of age and gender, further screening for gastrointestinal tumors should be done. Thirdly, imaging examination, which is widely used in hospitals at all levels, helps to judge the size of tumor, infiltration of surrounding organs and distant metastasis, and has important value in assessing tumor staging and treatment plan development. 1.B ultrasound, which can understand the situation of parenchymal organs such as liver, gallbladder and pancreas (the possibility of many kinds of primary cancer and metastatic cancer), is less valuable for gastrointestinal tumor itself. 2.CT can understand the location, size, depth of invasion, relationship with surrounding organs, lymph node metastasis or not, preliminary judgment of mass nature and assessment basis of tumor stage; it is one of the important examination items before surgery. 3.Nuclear magnetic resonance, i.e. MRI, which is complementary to CT and basically similar in meaning. 4.PET-CT, the full name is positron emission tomography/X-ray computed tomography. It has unique advantages in the diagnosis and efficacy assessment of tumors, heart and brain diseases, and is commonly used in the diagnosis, staging and treatment assessment of most tumors with precise localization, and is particularly suitable for determining whether there are distant metastases in gastrointestinal tract tumors, or understanding postoperative tumor recurrence. Fourthly, pathological examination. Pathological examination is the gold standard for tumor diagnosis. It can be divided into two types according to different ways of sampling: one is endoscopic biopsy, for mucosal lesions found in gastroscopy and colonoscopy, tissue biopsy is needed to clarify their nature, so as to provide pathological basis for the formulation of treatment plan. For example, the same polyp lesion, if the pathological examination results are malignant, radical resection surgery is required, while if it is benign, it can be removed endoscopically or local excision can be done. Secondly, the surgical resection specimen should be comprehensively taken to further clarify the tumor nature, differentiation, pathological type, lymph node metastasis and immunohistochemical examination if necessary, so as to provide exact basis for the development of tumor pathological stage, chemotherapy and radiotherapy program. 6.Treatment principle of intestinal malignant tumor For gastrointestinal malignant tumor, the current treatment principle is to adopt the comprehensive therapy of radical resection mainly by surgery and adjuvant chemotherapy, radiotherapy and immunotherapy. In terms of surgery, special emphasis is placed on early detection and early surgery. Whether it is gastric cancer, colon cancer or rectal cancer, if radical surgery can be performed at an early stage, most patients can achieve a survival period of more than 5 years, and a considerable number of patients can survive for a long time. On the contrary, if the tumor is already at an advanced stage (stage IV) at the time of surgery, less than 5% can survive for 5 years after surgery. For those patients who have lost the chance of radical resection, palliative surgery can also be used to improve symptoms and prolong survival time. Besides surgery, chemotherapy, radiotherapy and immunotherapy are also valuable for gastrointestinal malignancies. For a specific patient, is chemotherapy or radiotherapy needed? What chemotherapy or radiotherapy regimen is used? The length of the treatment course should follow the corresponding indications and guidelines. Recent clinical practice has proved that for advanced gastrointestinal malignancies, treatment with neoadjuvant methods such as chemotherapy or radiotherapy first, followed by surgery after tumor shrinkage and stage reduction, can increase the chance of radical resection and significantly improve surgical results and long-term survival chances.