Every year, about 1.2 million new cancer cases occur in China, 800,000 to 1 million die from cancer, and cancer deaths account for 13% to 14% of the total causes of death. “Expensive treatment is not realistic for developing countries, but by trying to apply the knowledge that has been accumulated, we should be able to effectively reduce cancer incidence and mortality,” noted Sturgeon Wilder, chair of the World Health Organization’s Commission on Cancer Specialization. The committee also believes that about 1/3 of cancers are preventable through health education programs and through prevention of known carcinogenic factors. Another approximately 1/3 of cancer patients can be diagnosed and treated early through early detection of cancer patients through screening. Another 1/3 of cancer patients, through active treatment, may still prolong their survival and improve their quality of life. Since the early 80s, experts in preventive medicine and social medicine have proposed the concept of tertiary prevention of cancer. 1. Grade I prevention is also called etiological prevention. It is aimed at preventing the occurrence of cancer, rather than eliminating it through treatment. The prevention method can be strictly stipulated by administrative orders and legal provisions to protect individuals and society from cancer-causing factors; it can also make use of radio, TV and newspapers to widely publicize cancer hazards and popularize cancer prevention and treatment knowledge, so that the public can correctly understand cancer, establish the correct concept that cancer can be prevented and treated, and build a safe and healthy lifestyle. 2.R-level prevention means early detection. It is to detect cancer at the earliest stage, or even at the pre-cancerous stage by applying special examination methods (such as cervical exfoliation cytology, breast examination, x-ray examination, etc.) and give timely treatment to control its development. In this way, not only can we reduce the treatment cost and avoid the development of advanced cancer, but also can significantly improve the cure rate and reduce the mortality rate. The most important method for early detection is cancer screening. In addition, regular physical examination and self-examination are also recommended. 3.m-level prevention Also known as clinical prevention or rehabilitation prevention. It is aimed at preventing the deterioration of the disease and preventing disability. Its method is to provide radical treatment for patients who can be cured through comprehensive multidisciplinary diagnosis and treatment, and correctly select reasonable treatment plan to achieve cure; provide palliative treatment and terminal treatment for patients who can no longer be cured to eliminate pain, restore physical strength, prolong survival time and improve life quality.