Esophageal cancer is one of the highly prevalent malignant tumors in the world. Especially in China, the annual incidence of esophageal squamous carcinoma is 260,000 new cases and 210,000 deaths, the number of incidence and deaths exceeds more than half of the world, so esophageal cancer is a malignant tumor with Chinese characteristics. Since the 1970s, the incidence of esophageal adenocarcinoma has increased significantly in Western countries such as Europe and the United States, and has now surpassed squamous carcinoma as the major histological type of esophageal cancer (accounting for 60% to 70%). However, in Asia, esophageal squamous carcinoma is still the main pathological type, accounting for more than 95%. The prognosis of esophageal cancer is poor, with half of the patients being advanced at the time of diagnosis, and the 5-year survival rate is only 5-7%. Even for patients who have the opportunity to receive surgical treatment, 90% of them may still have recurrence and metastasis. Although the diagnosis and treatment level of esophageal cancer has been significantly improved in recent years, the prognosis of patients is still not optimistic. Although there is a long way to go for effective prevention and treatment of esophageal cancer, proper understanding and knowledge of esophageal cancer is still one of the “mandatory courses” for ordinary people to prevent and treat esophageal cancer. The exact and specific cause of esophageal cancer is still unclear, but most scholars believe that it is the result of a combination of factors. Based on the information provided by the existing epidemiological data of esophageal cancer, it is believed that the occurrence of esophageal cancer has clear geographical distribution aggregation and ethnic differences, which may be related to the following factors in summary. Environmental factors Environmental factors usually cause the occurrence of malignant tumors because of the lack of certain protective substances or the existence of polluting substances that are harmful to human body in the environment, thus causing damage to tissues and organs that are difficult to be repaired or promoting their development, thus producing cancer. The lack of certain vitamins, trace elements, proteins and essential amino acids in the diet can cause epithelial proliferation and interstitial degeneration of esophageal mucosa, which can further cause carcinogenesis. The epidemiological findings of the above dietary component deficiencies leading to esophageal cancer were verified in population-based interventional trials. In areas with a high incidence of esophageal cancer, vitamin supplementation for people at high risk of esophageal cancer, i.e., those with esophageal epithelial hyperplasia, can delay and reduce the development of esophageal cancer. It has been shown that the lack of vitamin B2 (riboflavin) and trace elements such as iron, molybdenum and zinc in dietary composition is also related to the occurrence of esophageal cancer. 2.Nitrosamines in diet Nitrosamines are strong carcinogens, which mainly include nitrosamines and nitrosamides. The epidemiological survey results show that in Lin County, Henan Province, China, where the incidence of esophageal cancer is high, high levels of nitrate and nitrite can be detected in grain, sauerkraut and well water, and their levels are positively correlated with the incidence of local esophageal epithelial hyperplasia and esophageal cancer. 3, a large number of fungi in the environment and the toxins secreted by them Existing studies show that more than 10 kinds of fungal toxins can induce tumors in different organs of animals. Aflatoxin is one of the important causes of liver cancer. Epidemiological studies have found that fungal contamination in food in areas with high incidence of esophageal cancer is 2-15 times higher than in areas with low incidence. The toxins of Streptomyces interspersus and Fusarium cepacia isolated from grain in Lin County, Henan Province, can induce esophageal cancer in human embryos and esophageal and gastric cancer in rats. Life habits 1. The occurrence of esophageal cancer is closely related to the long-term stimulation and chronic damage to esophagus, while the chronic damage inducing factors are closely related to patients’ life habits. For example, eating irritating food such as hard and coarse food, hot soup, hot porridge, hot tea or pepper for a long time, or having bad habits such as fast-tan, poor chewing and overeating. These bad habits can cause chronic physical stimulation and damage to the esophageal mucosa, creating conditions for various carcinogens to enter the body, thus promoting the occurrence of esophageal cancer. 2.Long-term smoking and alcohol consumption Cigarette smoke and tar contain many carcinogens, such as benzo(a)pyrene, polycyclic aromatic hydrocarbons, nitroso compounds and epoxide, which are strong carcinogens and can induce cell damage and carcinogenesis. Some studies show that the incidence of esophageal cancer is 7 times higher among heavy smokers than among non-smokers. The risk of esophageal cancer from alcohol consumption is not clear, and the risk of esophageal cancer from alcohol with different alcohol content varies. Generally speaking, the higher the alcohol content or the higher the risk of esophageal cancer for long-term drinkers. 3. Lack of vegetables and fruits in the diet, lack of micronutrients and bioactive substances may be closely related to the occurrence of esophageal cancer. Other Causes of Chronic Esophageal Damage Besides lifestyle habits, various other physiological or pathological factors lead to the existence of chronic esophageal damage, which in turn leads to pathological changes such as interstitial changes or atypical hyperplasia of esophageal mucosal epithelial cells. In recent years, the incidence of esophageal adenocarcinoma in Western countries is increasing significantly, and studies have found a significant correlation with Barrett’s esophagus due to reflux esophagitis. Genetic factors Clinical studies have found that only a few people with similar pathogenic environmental factors have cancerous esophagus, suggesting that apart from external factors, personal genetic factors also play an important role in the development of esophageal cancer. It is also clinically found that the development of esophageal cancer often shows some family clustering phenomenon, and most of them are concentrated among blood relatives, which also suggests that genetic factors play a role in the development of esophageal cancer. However, the basic research on this issue is still in its initial stage.