所谓癌预防即排除有关的危险因素,如酒精、尼古丁、食物内的致癌物质等或摄入保护性因素,如维生素E、β-葫萝卜素或阿斯匹林。另外癌肿的预防还表示尽早识别上消化道的危险状况和病变,并通过对其进行治疗以阻止侵入性肿瘤的发生。这主要是指食管癌和胃癌,而不是指小肠癌(十二指肠除外)、胰腺癌和胆管癌。这类癌肿因临床症状少,多发现过晚,且不了解其具有早期诊断价值的癌前病 The so-called cancer prevention excludes relevant risk factors such as alcohol, nicotine, carcinogens in the food, etc., or intake of protective factors such as vitamin E, beta-carotene, or aspirin. In addition, the prevention of cancer also means that early detection of dangerous conditions and lesions of the upper digestive tract, and by treating them to prevent the occurrence of invasive tumors. This mainly refers to esophageal cancer and gastric cancer, but not to small intestine (excluding duodenum), pancreatic cancer and cholangiocarcinoma. This kind of cancer has too few clinical symptoms and it has been found too late, and it is unclear about precancerous disease with early diagnostic value.