The esophagus is the tube through which food passes, mainly composed of muscle fibers, 25-30 cm long and 2 cm in diameter, and is divided from the inside out into a mucosal layer, a submucosal layer and a muscular layer. The part of the esophagus connected with the stomach is called the cardia, and the muscles of the cardia open when eating and close after eating to avoid reflux of gastric juice. The gastric acid and gastric enzymes in the gastric juice are very corrosive. Once the pancreatic valve fails to close, the reflux of gastric juice can digest the mucous membrane of esophagus and cause cancer of the cells there over time. Esophageal cancer is a common malignant tumor in China, and the high incidence area is concentrated in Taihang Mountain area at the junction of Henan, Hebei and Shanxi provinces. Esophageal cancer is the most common malignant tumor in China. It is more common in men than women above 40 years old. Risk factors 1, dietary factors long-term hot food, rough and hard food, eating too fast, squatting eating and other chronic stimuli cause esophageal mucous membrane damage, resulting in esophageal epithelial inflammation and hyperplasia, forming precancerous lesions of esophageal cancer and gradually leading to cancer. 2.Nitrosamines and fungal toxins in sauerkraut, kimchi, smoked products, pickled products, moldy food, pond water and other chemical carcinogens such as nitrosamines and fungal toxins can change the structure of proteins and promote gene mutation to form cancer. 3.Nutritional factors such as lack of animal protein, vitamins and trace elements, such as vitamin C, A, B2, trace elements of zinc, magnesium, iron, etc., are all risk factors of esophageal cancer. Alcohol and tobacco can directly damage the esophageal mucosa and act as a solvent for carcinogens, which can cause carcinogens to enter the esophageal mucosa. According to the data, the incidence rate of heavy drinkers is more than 50 times higher than that of basic non-drinkers; the incidence rate of smokers is 7 times higher than that of basic non-smokers; the incidence rate of heavy drinkers and smokers is 156 times higher than that of non-drinkers and non-smokers. Esophageal cancer has certain genetic tendency, and it can occur in the same generation or within several generations in a family. Oncogene research has confirmed that the inactivation of oncogenes such as Rb and P53, and the activation of proto-oncogenes such as H-ras, C-myc and hsl-1 by environmental factors are related to the development of esophageal cancer. Abnormal manifestations 1. Early stage is atypical and easy to be ignored, sometimes light and sometimes heavy, with different duration, or even asymptomatic. (1) Choking sensation in the throat: when swallowing food, it is like a gas obstruction in the esophagus, which can subside on its own without treatment, but reappears in a few days, often related to emotional fluctuations. (2) Dry and tight feeling in the throat: It may be caused by poor peristalsis of the esophagus and reflexive contraction of the esophagus. (3) Foreign body feeling in the esophagus: it seems that there are similar rice grains or vegetable leaves attached to the wall of the esophagus, which cannot be swallowed, and water flushing is not effective. (4) The feeling of slow stagnation of food passage: the esophageal wall seems to have adhesion, affecting the downward movement of food, and sometimes the same feeling is felt when drinking water. (5) Pain in the throat or behind the sternum: the nature of the pain can be burning-like, pinprick-like or pulling and rubbing-like, and the pain is aggravated when swallowing rough, overheated or irritating food, which usually appears at the beginning of the meal and gradually decreases, and disappears after the meal is over, and this pain can be relieved by medication, but reappears several days later if the meal is improper or when there are mood swings. (6) Stifling discomfort behind the sternum: Patients show discomfort in the chest, belching, sighing, etc.. There are also a few patients who feel a sinking back, pain and radiation to the right chest. 2.Middle and late stages (1) Pain under the glabella and epigastric region, which is aggravated when eating. In the late stage, persistent chest and back pain may occur due to mediastinal invasion. (2) Food regurgitation: regurgitated material contains mucus, sometimes bloody, mixed with next-day food and necrotic detached tissue pieces. (3) Gradually increasing dysphagia. (4) Other manifestations: hoarseness due to lymphatic metastasis compressing the laryngeal recurrent nerve; left supraclavicular mass as a manifestation of supraclavicular lymph node metastasis; vomiting of mucus, which is foamy in nature and can reach 500~3000ml per day in severe cases, caused by esophageal obstruction, which prevents saliva and esophageal secretion from flowing into the stomach, tumor infiltration and inflammation causing reflexive increase in secretion of esophageal and salivary glands. Vomiting blood and black stool are caused by tumor erosion and esophageal perforation. Prevention of esophageal cancer (1) Improved drinking water: Drinking water is one of the main sources of carcinogenic nitrosamines and their precursors into human body, so we should stop drinking dry well water, pond water, river water and spring water, change shallow well water to deep well water, and it is better to popularize filtered or disinfected tap water, and it is better to use river water or deep well water as tap water source. Families provide their own drinking water purifier. (2) Prevention of mold and poisoning: ① choose high-quality grain seeds, to prevent collapse and insect infestation. ② crop harvest should not miss the farming time, and strive to harvest, fast play, fast sun, fast into the warehouse. ③ strengthen grain bin management, keep ventilation, dry, grain temperature should be controlled to 13 ° below, relative humidity at 70% to 75%. Every rainy season, when the corn cob can not be threshed, it can be hung in a ventilated and dry place, and dried in the sun as soon as possible after the rain, if the grain is wet and damp from the rain, it can be professionally de-wetted. ④If the grain has been moldy or contaminated by mycotoxins, the moldy, broken, insect-infested grain can be picked and removed or de-toxified by drugs under the guidance of professionals. ⑤ Pay attention to the prevention of mold during food processing, strengthen food hygiene management, and eliminate moldy food from the market. (3) Cultivate good dietary hygiene habits: change the habit of chewing betel nut, tobacco, do not eat pickles, hard food, irritating food, pickled, fried, moldy food, do not eat leftovers, do not eat unclean food such as unwashed fruits and vegetables, do not use toxic plastic bags, paper packaging food. Eat more fresh vegetables, fruits, soy products, dairy products. (4) Improve the nutritional structure: The nutritional composition of various foods, especially trace elements, varies, therefore, the variety of food should be diversified to balance nutrition and correct the lack of trace elements. Garlic and kiwi can block the synthesis of nitroso compounds and can be consumed appropriately. (5) Cultivate good eating style and eating habits: chew slowly, eat three meals quantitatively and regularly, change bad habits such as hot drinks and hot food, eating too fast and squatting to avoid long-term adverse stimulation of the esophageal mucosa. (6) Quit smoking and limit alcohol, and prohibit smoking in public places. 2.Actively carry out screening of high-risk groups ①Regular screening of people with precancerous lesions and precancerous diseases of esophagus. ②Susceptible people with family history and residents in areas with high incidence of esophageal cancer should pay attention to change their original bad eating habits and adjust their lifestyles as soon as possible. Those who are over 30 years old and have swallowing discomfort and abnormal sensation behind the sternum should seek medical consultation and regular examination. Upper gastrointestinal imaging is recommended every 2 years. For high-risk groups and those with high-risk factors, we recommend gastroscopy once a year. 3.Actively treat precancerous diseases ①Esophageal inflammation: positively correlated with the occurrence of esophageal cancer. ②Esophageal epithelial hyperplasia: the cancer rate of severe esophageal hyperplasia is 26.6%~30.3%. Esophageal epithelial hyperplasia is 140 times of the cancer rate of normal esophagus. ③Esophageal ulcer: it occurs on the basis of esophageal inflammation and is closely related to esophageal cancer. ④Esophageal mucosal leukoplakia: it is related to the occurrence of esophageal cancer. ⑤ Esophageal scar stenosis: ulcer, chronic inflammation and chemical burns can cause esophageal scar stenosis. Its cancer rate is higher than general cases. Early signs of esophageal cancer ①Choking sensation in the throat. ②Sense of dryness and tightness in the throat. ③ Foreign body sensation in esophagus. ④Sensation of slow stagnation of food or water passage. ⑤ Pain in the throat or pain behind the sternum. ⑥Sense of stuffiness and discomfort behind the sternum, or back sinking, pain and radiation to the right chest. The key to the treatment effect of esophageal cancer is early detection. To be alert to the early signs of esophageal cancer and to go to a specialized oncology hospital for examination in time is an important means of early detection of esophageal cancer.