Can tumors be prevented? This is a question of great concern to everyone, and no wonder, with the rapid development of science and technology, the increasing seriousness of environmental pollution and the change of people’s living habits, the incidence of tumor is increasing year by year, and since the 21st century, cancer has become the number one killer of human health. According to statistics, there are nearly 2 million new cancer patients and about 1.5 million deaths due to cancer in China every year, and the incidence rate of cancer is still increasing at a rate of 2.5% per year. Among them, the incidence rate of lung cancer is the highest. In a study report published by International Agency for Research on Cancer (IARC) in October 2005, it is pointed out that according to the current trend of cancer incidence, the incidence of cancer worldwide will increase by 50% by 2020, and the number of new cancer patients worldwide will reach 15 million every year, among which, the highest incidence of lung cancer will reach 1.2 million. However, people know very little about cancer, and they are all afraid of talking about cancer. Some people wrongly believe that cancer is incurable, so they miss the opportunity to treat cancer that could be cured; some people only carry out a certain treatment, such as surgery, chemotherapy or some unproven treatment methods from hearsay, so that the treatment effect is far from what it should be. According to the statistics of UICC (International Union Against Cancer), more than half of the cancer patients are completely curable, and the other part can improve the quality of survival and prolong the survival time through comprehensive treatment. Not only that, a large number of facts also show that 70% of cancers can be prevented in advance. Smoking is an important cause of lung cancer, esophageal cancer and oral pharyngeal cancer; long-term alcoholism can cause liver cancer and stomach cancer; pickles and vegetables heated repeatedly overnight can produce nitrite, which has obvious carcinogenic effect; aflatoxin produced by moldy food has carcinogenic effect; food coloring and smoked and baked food have carcinogenic effect; long-term consumption of high-fat diet is related to breast cancer and rectal cancer; many tumors are related to As long as people change their bad eating and living habits and maintain mental health, they can prevent most cancers! Based on a large number of facts, the World Cancer Research Fund (WCRF) released the 200-page landmark document “Cancer Prevention Policies and Actions” on February 26, 2009. Written by 23 of the world’s leading experts, the recommendations are based on evidence from evidence-based medicine. The document tallied country-by-country information and concluded that 1/3 of the 12 common adult cancers are preventable in high-income countries (e.g., the United Kingdom and the United States) and about 1/4 in low-income countries (e.g., our own). This figure does not include the results of smoking bans, which alone can reduce cancer by 1/3, but because these factors are interrelated, the two figures do not simply add up. After controlling diet, increasing activity and maintaining weight, cancer can be prevented in China: 44% of esophageal cancer, 44% of oral and throat cancer, 38% of lung cancer, 34% of endometrial cancer, 33% of stomach cancer, 20% of breast cancer, 17% of colorectal cancer, 14% of pancreatic cancer, 8% of kidney cancer, 6% of liver cancer and 6% of gallbladder cancer, totaling an average of 27%, or 20% if all cancers are counted. In the United Kingdom and the United States, the prevention of endometrial cancer is 56% and 70%, colorectal cancer 43% and 45%, and breast cancer 42% and 38%, for a total average of 39% and 34%, or 26% and 24% for all cancers. In addition, early treatment of precancerous lesions is also the main way to prevent tumors. It can be seen that most of the tumors can be prevented. As long as we change the bad living habits, change the bad eating habits, maintain a good state of mind and actively treat precancerous lesions, we can prevent tumors well.