There is no such thing as what cancer cells are most afraid of. Cancer cells are caused by chemical, physical, biological, genetic and other factors over a long period of time. For high-risk groups, preventive measures should be taken actively, while patients suffering from cancer need to receive regular treatment actively. Most of the cancers occur in people who live irregularly for a long time and have bad habits such as long-term smoking, drinking and staying up late. In daily life, we should prevent cancer by avoiding these bad habits, avoiding eating too fast, and eating less hard, too hot, high salt, fried, pickled and moldy food. In addition, avoid excessive exposure to sunlight and long-term contact with fuel, leather, rubber, plastic, paint and other chemicals, and also need to stay away from high radiation areas. For people diagnosed with cancer, comprehensive diagnosis is needed, and appropriate treatment programs, such as surgery, radiotherapy, chemotherapy, etc., should be selected according to the stage of the cancer and the patient’s specific situation. Therefore, both prevention and treatment of cancer are very important. It is suggested that everyone should correct their bad living habits, and once diagnosed with cancer, they should be treated as early as possible in order to avoid deterioration of the condition.