Esophageal cancer, also called esophageal cancer, is a malignant tumor occurring in the epithelial tissue of the esophagus, accounting for 2% of all malignant tumors. The age of onset is more than 40 years old, and men are more than women, but in recent years, there is a trend of increase in the number of patients under 40 years old. What are the causes of esophageal cancer? At present, it is believed that the development of esophageal cancer may be related to the following factors: 1) Nitrosamines: Nitrosamines are a group of strong carcinogenic substances. Residents of Linxian County, Henan Province, a high incidence area of esophageal cancer, like to eat sauerkraut, which contains nitrosamines. It has been proved that the amount of sauerkraut consumed is directly proportional to the incidence of esophageal cancer. (2) Mold: Some people use moldy food to feed rats for a long time and induce esophageal cancer. 2. Nutrition and trace elements: lack of vitamins, proteins and essential fatty acids in the diet can make the esophageal mucosa hyperplasia and mesenchymal degeneration, which can further cause cancer. Lack of trace elements such as iron, molybdenum and zinc is also related to the occurrence of esophageal cancer. Genetic factors: The susceptibility of the population is related to heredity and environmental conditions. Esophageal cancer has significant family aggregation phenomenon, and families with three or more generations of esophageal cancer patients are common in high incidence areas. Dietary habits: Long-term smoking, drinking strong alcohol, eating hot food for a long time, chewing too hard food, etc. are related to the occurrence of esophageal cancer. Pre-cancerous lesions and other disease factors: such as esophageal epithelial hyperplasia, esophageal diverticulum, esophageal mucous membrane injury, Plummer-Vinton syndrome, chronic esophageal inflammation, esophageal scar stenosis, esophageal ulcer, hiatal hernia, esophageal leukoplakia, pancreatic achalasia and so on, are all regarded as pre-cancerous lesions or pre-cancerous diseases of esophageal cancer.