As with other tumors, the etiology is unknown and may be related to dietary factors, environmental factors, genetic factors, and H. pylori infection. Additional precancerous changes such as chronic atrophic gastritis, gastric ulcer, gastric polyps, epithelial cellular hyperplasia of the gastric mucosa and heterotypic hyperplasia of the gastric mucosa epithelium exist. The incidence of cardia cancer in some Asian, North American and European countries is increasing year by year. Therefore, a multidisciplinary and comprehensive study of cardia cancer is needed to improve its early diagnosis and treatment as well as the 5-year survival rate after surgery.
The etiology of pancreatic cancer is complex. It is generally believed that living environment and diet are the two main carcinogenic factors for various cancers of the human upper gastrointestinal tract, and there may also be a relationship with gastroesophageal reflux and esophageal hiatal hernia. Among the histogenesis of gastric cancer, gastric ulcer, gastric polyp (adenoma) and chronic atrophic gastritis were considered as precancerous lesions of gastric cancer in the past. Recent studies have found that the chances of cancer occurring in these cases are very small. As a special type of gastric cancer, pancreatic cancer is not related to the histogenesis of pancreatic cancer. It is more commonly believed that pancreatic cancer originates from cervical stem cells of pancreatic gland with multidirectional differentiation potential, and the stem cells can form adenocarcinoma with pancreatic or glandular epithelial characteristics. Light microscopy, electron microscopy and histochemical studies have revealed that pancreatic cancer is of mixed type, which strongly supports this view. Atypical hyperplasia is a precancerous lesion of pancreatic cancer, and it is also a key pathological process shared in the ulcers, polyps, and atrophic gastritis mentioned above that are associated with the development of pancreatic cancer. They may become cancerous only when they undergo atypical proliferative changes, of which the colon type occurs mostly with atypical proliferative nature.
Schottenfeld’s (1984) study on the epidemiology of esophageal cancer in North America and Europe found that alcohol consumption and smoking are important risk factors for esophageal squamous carcinoma, but their role in the pathogenesis of esophageal adenocarcinoma with cardia is not clear.