“It is understood that most people’s understanding of cancer only stops at the stage of seeing flowers in the fog, and for a long time, people think that cancer is an incurable disease, and once they suffer from cancer, they will definitely die. This concept and impression make people fear talking about cancer, and they are even influenced by the fear of cancer and are afraid to go to oncology hospitals for treatment, thus delaying the treatment. So what is cancer? Carcinoma is derived from the Latin word “Karkinos”, “Karki-nos” means crab. The word “Karki-nos” means crab. It is chosen to describe the growth and characteristics of cancer as well as its harmful effects on human health. A tumor is a localized mass formed by the uncontrolled growth of many abnormal cells in the process of reproduction of body cells under certain stimuli, which is called “tumor”. Due to its biological characteristics, growth pattern and the degree of harm to human body, there are benign and malignant tumors. Benign tumors grow slowly, have clear boundaries with surrounding tissues, do not metastasize, and are not harmful to human health. Malignant tumors, usually called “cancer”, grow rapidly and can infiltrate into the surrounding tissues and metastasize to other parts of the body. So can cancer be prevented or not? The World Health Organization Advisory Committee clearly stated in 1981 that 1/3 of cancers can be prevented, 1/3 of cancers can be cured if diagnosed early, and 1/3 of cancers can reduce pain and prolong life. The formation of cancer cells does not happen overnight. Any normal cells need to be induced and stimulated for more than 10 years or decades before they can be transformed into cancer cells, therefore, the latent period of cancer can be more than 10 years before it is detected. In this regard, we have to admire our ancestors. Thousands of years ago, in the Yellow Emperor’s Classic of Internal Medicine, there was an insightful statement that “the superior worker does not treat the disease, but treats the disease before it occurs”, putting forward the idea that prevention is better than cure. A large number of investigation data have confirmed that the factors causing cancer are multifaceted, but to a large extent, they are attributed to people’s bad behaviors and living habits. A report of the World Health Organization Cancer Expert Committee points out that 80% of cancers are caused by poor lifestyle and environmental factors; 35%-40% of cancers are related to unscientific and unreasonable diet; 30% of cancers are caused by smoking, and passive smoking is more harmful; 5% of cancers are related to alcohol consumption. People call such cancers caused by bad behaviors and habits as “lifestyle cancer”. Specifically, we need to pay attention to the following aspects: 1. Emotional and mental factors Traditional Chinese medicine believes that emotional and mental disorders are one of the causes of tumors. Excessive changes of emotion and mental stimulation can lead to Qi disorder and dysfunction of internal organs. For example, excessive stress, thinking, sadness, grief, fear and anger can affect the drainage function of liver and lead to the phenomenon of Qi disorder such as liver qi discomfort or liver qi reversal, which will lead to Qi stagnation and blood stasis, and the loss of harmony between internal organs and tumor. Modern medicine also believes that people with eccentric personality, dull and depressed, narrow-minded, sentimental, pessimistic, jealous, irritable and sulking are prone to be attacked by cancer. The reason is that bad emotions can affect immune function and endocrine, lowering immune function and unbalancing endocrine, which is a strong “cancer promoter”; while optimism can improve human immune function and is the best “antibody”. Japanese experts found that after cancer patients laughed, the active substances in their bodies that naturally kill cancer cells were greatly increased. Therefore, it is necessary to cultivate a cheerful and optimistic character, learn to self-regulate emotions, be magnanimous, laugh a lot and ensure mental health. 2. Dietary factors There is an idiom in China that “disease enters through the mouth”, which is true for many diseases, including the occurrence of certain cancers. In the First International Conference on Nutrition and Oncology held in April 1991, R. Doll, a famous British epidemiologist of oncology, spoke: a reasonable diet can reduce the mortality rate of stomach and colon cancer by 90%, endometrial cancer by 20%, gallbladder cancer, pancreatic cancer, cervical cancer, oral cancer, nasopharyngeal cancer and esophageal cancer, and can reduce the total mortality rate of cancer by 10%. This is also confirmed by the fact that long-term studies have found that the occurrence of esophageal cancer is related to factors such as nitrosamines in food or drinking water, mold contamination, genetic and nutritional imbalance, etc. Through the implementation of comprehensive prevention and control measures such as changing water, food mold prevention, changing nutrition and dietary habits in areas with high incidence of esophageal cancer in China, the death rate of esophageal cancer in the above areas has shown a decreasing trend. Therefore, we have to carefully control the diet. The American Cancer Society recommends the following dietary guidelines for cancer prevention: 1. maintain ideal body weight; 2. eat a varied and moderate diet; 3. include a variety of vegetables and fruits in daily diet; 4. eat more foods with high fiber content; 5. limit the intake of alcohol; 6. reduce the intake of salted, smoked, and nitrate-containing foods. Pay attention to a reasonable diet, this is the work that everyone should start doing now. If you do do this job well, you have taken a welcome step on the road of cancer prevention. Regular physical exercise, 30 minutes a day, no less than 5 days a week. Exercise can improve the body’s immune function, make the qi and blood flow smoothly and push out new energy. Some cancer patients’ cancer cells can recede on their own after physical exercise. Therefore, if we insist on exercising and persevere, we will be able to strengthen our body and prevent and cure diseases. Physical exercise can cultivate and mobilize the anti-cancer ability of the body. Modern medicine believes that factors in the body play an important role in the occurrence of tumor, and the theory of Chinese medicine also believes that cancer occurs due to the lack of positive energy in the human body, internal invasion of external evil, coupled with poor emotion, resulting in the imbalance of yin and yang in the body, loss of harmony between internal organs, loss of regulation of qi and blood, and obstruction of meridians, which leads to internal evil, whether external evil or internal evil, the guest in the human body, after a long time, accumulation of tumor. Thus, it can be seen that the lack of positive energy is the root cause of tumor formation, and “the entrapment of evil energy” is the basic condition for tumor formation. Therefore, “supporting the righteousness and eliminating the evil” has become an important part of tumor prevention in Chinese medicine. Chinese medicine often adopts herbal medicine, qigong, acupuncture, medicinal food, dietary supplements, exercise and other specific methods to nourish the body’s positive energy and maintain the stability and balance of the internal environment of the body, so as to achieve “the spirit of healing when yin and yang are secret”. At present, chemopreventive agents that interfere with tumor generation with drugs are being researched, and the use of Chinese herbal medicine to strengthen the body for tumor prevention is worthy of strong advocacy. If one of the medical achievements in the 20th century is the clarification that cancer is completely preventable, then the 21st century will be a new era for people to take action to prevent cancer themselves. No one can guarantee that he or she will not have cancer, and it is impossible to have a cancer-free society. However, everyone can have the confidence to prevent cancer themselves, rely on their knowledge, wisdom and perseverance, choose the best lifestyle, exclude and avoid all factors and risks that may cause cancer, take the responsibility to promote health, use science to realize the wish of not having cancer, and use knowledge to save lives.