What is esophageal cancer? Esophageal cancer is a malignant tumor that occurs in the epithelial tissue of esophagus, accounting for 2% of all malignant tumors. About 200,000 people die of esophageal cancer worldwide every year, and China is a high incidence area for esophageal cancer, which is the second most common cause of death after stomach cancer. However, in recent years, there is a growing trend for those under 40 years old. The occurrence of esophageal cancer is related to the chronic stimulation of nitrosamines, inflammation and trauma, genetic factors, and the content of trace elements in drinking water, food and vegetables. However, the exact cause is not well understood and needs to be investigated.