大量研究表明 ,胃癌的发生是一个涉及多个基因改变的多步骤过程。在发生恶性肿瘤之前常经历多年持续的癌前病变 ,目前一致认可的模式为 :慢性萎缩性胃炎→胃粘膜肠化生→胃粘膜不典型增生→胃癌。由于胃癌的病因还不完全清楚 ,实施针对病因的一级预防比较困难 ,因此 ,对癌前病 Numerous studies have shown that the occurrence of gastric cancer is a multi-step process involving multiple genetic changes. Before the onset of malignant tumors, it often undergoes many years of precancerous lesions. The currently accepted pattern is: chronic atrophic gastritis → intestinal metaplasia of gastric mucosa → gastric dysplasia → gastric cancer. Since the cause of gastric cancer is not fully understood, it is difficult to perform primary prevention against the cause. Therefore, for precancerous conditions