In the past 20 to 30 years, under the joint efforts of scientists from various countries, the mystery of cancer has been gradually revealed, and the correct understanding is becoming a reality step by step. It is only a matter of time before this understanding replaces the erroneous understanding of the past and becomes widely accepted. For the first time since 2006, the total number of cancer deaths worldwide, especially in the United States, has been on the decline. The World Health Organization (WHO) and other international organizations have also changed their approach, redefining cancer as an “incurable disease” to a “chronic disease that can be treated, controlled, or even cured”. The domestic medical oncologists are also experienced in the field of oncology. Domestic also has senior authority of medical oncology Sun Yan academician clearly pointed out that: “In fact, for ordinary people, there will be more and more cancers in the future may be like diabetes, is only a kind of common chronic diseases. As long as prevention is strengthened, early detection and early treatment, coupled with new drugs that are more and more accurate, cancer is not so terrible.” This encouraging news makes us realize that cancer is controllable and curable, and that “cancer ≠ death”, so what does “chronic disease” mean? It means it happens slowly and heals slowly. Therefore, we believe that this is a fundamental change in the concept of cancer. 20 years ago, there was a discussion about the classification of cancer into which category of disease, and at that time, experts preferred to classify cancer into a single category of disease. However, after more than 20 years of discussion, the World Health Organization (WHO) officially announced in 2006 that cancer is a chronic disease. How do you understand that WHO defines tumor as a chronic disease? Does it mean that there is a change in the rules of treatment for clinicians? First, the pathogenesis of cancer is a long process. Figuratively speaking, the cancer problem we see is only the tip of the iceberg, and there is a big piece underneath. If we compare it to a play, what we have seen is only the last act, which is already the epilogue, and we have not seen the process of the occurrence and development of cancer. Since it has been recognized that there is a very long process in the occurrence of cancer, emphasis should be placed on prevention and early detection and treatment. In this sense, to identify cancer as a chronic disease is to move the focus of clinical work forward. In fact, there is a consensus that cancer prevention and treatment must be moved forward in order to produce results. Because these cancer-causing influencing factors existed 30 years ago, people have sufficient time to carry out prevention, achieve early detection, and completely block it at an early stage. If we do not move forward and let the cancer develop to an advanced stage, we will only see the worst consequences: patients suffer, doctors work hard, and it also makes people feel that cancer is a very incurable disease. The second is to find a way to turn the cancer that has developed clinically into a chronic disease, so that the cancer progresses at a slower rate. Let cancer be controlled like diabetes and hypertension, and even allow patients to live peacefully with cancer for many years. Currently, we have many patients who can survive well with cancer with treatment. Defining cancer as a chronic disease is conceptually positive and proactive, and leaves a lot of room for people to fight it. It also fully emphasizes the importance of improving the quality of survival of tumor patients and its outstanding significance. The strategy for cancer has shifted from “seek and destroy” to “target and control”, and a goal has been set for 2015: “eliminate suffering and reduce deaths”. In other words, instead of focusing on “destroying” cancer cells and “curing” cancer, people are advocating a different way of thinking, one that is gentler, non-toxic, and less invasive, to slow down the growth of cancer cells or reduce their size. At the same time, more efforts are made to improve the quality of life of cancer patients and prolong their survival time.