大肠癌的发生并非由单一因素所致,而是一个多期过程。正常粘膜经腺瘤发展到癌肿的组织学进程是由多年内发生的一系列基因变化累积所致。此缓慢逐步的进展,为初级预防(营养预防,药物预防)和二级(筛查)预防提供了许多良机。流行病学和动物实验已为大肠癌指明众多有前景的预防药物,包括大分子物质、微量营养素(低脂肪、高纤维、多蔬菜饮食,钙、硒、 The occurrence of colorectal cancer is not caused by a single factor but a multi-phase process. The histological progression of normal mucosa through adenomas to cancer is caused by a series of genetic changes that have occurred over many years. This slow and gradual progress provides many opportunities for primary prevention (nutrition prevention, drug prevention) and secondary (screening) prevention. Epidemiology and animal experiments have indicated many promising preventive drugs for colorectal cancer, including macromolecular substances, micronutrients (low-fat, high-fiber, multi-vegetable diet, calcium, selenium,