Although tumor is an ancient disease, it is still a rare disease in the world until the beginning of last century. In the past half century, the incidence of tumor has been increasing year by year, and its status in the medical field is becoming more and more important, and it has become a multi-morbidity and common disease, and one of the main causes of death, which seriously threatens people’s health. To date, tumors have become a major disease burden worldwide, with approximately 11 million new cases occurring each year. In the past few years, chronic diseases (or non-communicable diseases), represented by malignant tumors (cancer), cardiovascular diseases, and diabetes, are becoming more major long-term threats, both worldwide and in China. on May 19, 07, the World Health Organization clearly pointed out in its latest published report that non-communicable diseases are becoming the most deadly human “killers”. Among them, cancer ranked first. According to the statistical report released by World Health Organization (WHO) in 2002, it is expected that about 7.6 million people will die from tumors in 2005 worldwide, 1.6 million in China. According to the current trend of cancer incidence, it is estimated that the incidence of cancer worldwide will increase by 50% in 2020, and the number of new cancer patients worldwide will reach 15 million annually. The most common cancer incidences worldwide are lung, stomach, colorectal, liver and breast cancers. At the same time, cancer mortality rates are rising, and their order in the disease mortality spectrum has risen from 9th place 50 years ago to 2nd place in the 1990s, and now tops the list. The most common cancer deaths are lung, stomach, and liver cancers. In conclusion, there is an overall upward trend in cancer incidence worldwide, with lung, breast, and colorectal cancers being among the cancers that have increased significantly. However, there are also a few tumors with decreasing trend in some countries, among which cancers with significant decrease include stomach cancer, cervical cancer, etc. The main causes of tumor incidence and mortality continue to rise The main risk factors of tumor include tobacco, alcohol, viruses and infections, radiation and radiation, diet and nutrition, environmental exposure, genetic susceptibility and so on. Among them, the increase of tobacco and alcohol consumption and the impact of modern lifestyle on lung cancer, digestive tract cancer, and breast cancer are intensifying, and the change of diet and nutrition is expected to lead to the decrease of stomach and esophageal cancer. The control of viral infection and the application of hepatitis B vaccine and HP vaccine will have a positive effect on the decline of liver cancer and cervical cancer. 1. Aging population In the past half century, with the improvement of living standard and the development of medicine and health, people’s average life expectancy has been increasing, and the incidence and mortality of cancer will also increase with the increase of life expectancy, people’s bad living habits and environmental pollution, and undoubtedly the number of tumor patients will also continue to increase. 2. Smoking Smoking leads to the increase of cancer incidence, and the cancer related to smoking will increase significantly in the next 30 years. 3. Influence of lifestyle and dietary structure According to the dynamic changes of common tumors in the world, it can be determined that people’s lifestyle and dietary structure have obvious relationship with the occurrence of tumors. 1/3 of cancers are related to diet, which is theoretically second only to smoking from the perspective of prevention. Nitrosamines in pickled foods are closely related to esophageal cancer, stomach cancer and nasopharyngeal cancer; aflatoxin in moldy foods is a strong liver cancer-causing substance; benzopyrene, a polycyclic aromatic hydrocarbon in barbecued foods, is related to the occurrence of stomach cancer and lung cancer; high-fat diet may be related to colon cancer, breast cancer and prostate cancer; over-salty foods should also be avoided, as salt may promote the occurrence of stomach cancer; obesity and physical activity caused by eating too much are related to many cancers, especially the reduction of physical activity. Reduced obesity and physical activity caused by excessive eating are related to many cancers, especially breast cancer, colon cancer and endometrial cancer. 4.Environmental pollution Environmental factors such as living environment pollution, occupational environment pollution and air pollution are important factors that further lead to cancer. 5.Infectious factors 16% of cancers are related to infections, while in developing countries, it reaches 22%. For example, hepatitis B virus and primary liver cancer, herpes virus and cervical cancer and anal cancer, Helicobacter pylori and stomach cancer and lymphoma, EBV and lymphoma and nasopharyngeal cancer, HIV and Kaposi’s sarcoma and lymphoma, schistosomiasis and bladder cancer, liver fluke mixed with bile duct cancer, etc. 6. Some cancers are related to radiation, environmental pollution, occupational exposure, hormones, drugs, fertility, food additives, etc. However, lifestyle is only an important aspect of cancer occurrence, but not the only one, and genetic aspects should not be ignored. 7.With the development of medicine, many serious threats to human health in the past have been better controlled, and their morbidity and mortality have been greatly reduced. However, the cause of tumor is still not completely clear, and there is no very effective treatment measures yet, so it leads to the increase of tumor morbidity and mortality. 8. Due to the development of modern medical science, there are more accurate and modern diagnostic methods, coupled with the popularization of oncology knowledge, the rate of tumor diagnosis has improved, so that the statistical figures will also increase. Therefore, it is not difficult to understand that people are more and more concerned about such diseases as tumor, on the one hand, because it is really a kind of disease that is difficult to subdue, on the other hand, it also marks the continuous development of health care in China. Oncology has attracted the attention of all parties. 9. Genetic susceptibility The study of genetic susceptibility or germline (germline) gene mutation has gained extensive attention. For example, the lifetime risk of breast cancer in family members of patients with the BRCA1 gene for breast cancer can reach 70%. Cancers that are hereditary or caused by genetic mutations occur at an earlier age than cancers caused by factors such as the environment. Familial cancers include retinoblastoma, breast cancer, liver cancer, and colon cancer. Certain genetically predisposed oncogenes may be more susceptible to environmental factors, such as cytochrome P450, the enzymes CYP2D6 and CYP2A6, which are associated with the metabolism of nicotine; it is thought that people who lack these two enzymes smoke less and quit easily. The roles of environmental and genetic susceptibility are sometimes not easily distinguished, and in fact the two may interact. For example, the main risk factors for breast cancer include reproductive, fertility and hormonal factors (early onset, late onset or infertility), nutritional diet (high fat, high calorie diet), family history, etc. Lack of physical activity and alcohol consumption can also increase the risk of breast cancer. Excessive intake of salted fish can increase the risk of nasopharyngeal carcinoma, but genetics and EBV can play a synergistic or strengthening role. III. Current situation of tumor incidence in China According to academician Sun Yan from Cancer Hospital of Chinese Academy of Medical Sciences, the incidence of cancer in China has been on the rise in the past 50 years, with more than 2.2 million new cases per year and changes in cancer spectrum. In the past 20 years, the mortality rate of cancer in China has increased by 29%, and one out of every four or five deaths is caused by cancer, which is the top cause of death. 2002 statistics from China’s health department already pointed out that cancer has replaced cardiovascular diseases as the number one killer threatening people’s health in China. According to statistics, in 2006, the incidence rate of malignant tumors in China was 126.02/100,000 and the mortality rate was 116.10/100,000. According to the results of the third national survey on causes of death in China released by the Ministry of Health on April 29, 2008, cerebrovascular diseases and malignant tumors have become the top two causes of death in China, accounting for 22.45% and 22.32% of the total number of deaths, respectively. Malignant tumor is the first cause of death in urban areas (25.0% of all deaths in urban areas) and the second cause of death in rural areas (21.0%). Lung cancer has replaced liver cancer as the first cause of death from malignant tumors in China (accounting for 22.7% of all deaths from malignant tumors). The most common cancers for men are: lung cancer, stomach cancer, liver cancer, esophageal cancer, and for women are: breast cancer, esophageal cancer, stomach cancer, lung cancer, liver cancer, cervical cancer. To some extent, the rising cancer incidence and mortality in China is also a “by-product” of the growth of life expectancy, but the “aging age” is not the only answer to the growth of cancer. The “age of aging” is not the only answer to cancer growth. This is particularly evident in some specific cancers. 2. Poor lifestyle and unclean drinking water are an important cause of cancer. Lifestyle that affects cancer, besides smoking, poor diet is a causative factor of cancer occurrence second only to smoking. Lung cancer has long replaced liver cancer as the top cancer death rate in China, and what is particularly worrying is that the peak of lung cancer death in China is far from coming. The dietary structure of the Chinese population has undergone an obvious trend of “westernization”, and overweight and obesity in urban and affluent rural areas is also one of the important reasons for the rise of cancers such as colon and rectal cancer and breast cancer. 3. Some cancers are also related to sexual and reproductive habits. For example, the average age of menarche for women today is much earlier and the age of childbirth is much later, while the secretion of large amounts of estrogen can contribute to breast enlargement and increase the risk of breast cancer. Breast cancer mortality among Chinese women has almost doubled in the last 30 years, second only to lung cancer in terms of rate of increase. Even according to the standardized mortality rate, it has increased by more than 30%. 4. Environmental pollution Environmental factors such as living environment pollution, occupational environment pollution and air pollution are further important factors leading to cancer. At the end of March this year, at the Academic Summit on the Progress of Oncology in China held in Beijing, Prof. Zhao Ping, President of Cancer Hospital of Chinese Academy of Medical Sciences, worriedly said, “Our living standard is improving, but the living environment is further deteriorating. 5. The Pain of Urban-Rural Disparity Lung cancer occupies the top position among the causes of cancer death among urban residents in China. The situation is different in rural areas, where liver cancer is the leading cause of cancer death, and the death rates of stomach, esophageal and cervical cancers are also higher than those in cities. 6. Other In addition to the above factors, in many economically less developed rural areas, farmers not only lack the basic knowledge of cancer prevention and control, but also lack sufficient payment ability to deal with the threat of cancer. Once cancer is detected, the high cost of cancer treatment, which is often tens of thousands of dollars, is again almost astronomical for these farmers’ families; some people simply choose to give up treatment and wait for death in helplessness. “Instead of opting for treatment and dragging the whole family to death, it is better to simply leave it to fate and give the whole family a way to live.” This kind of pathos and fatalistic so-called “rational choice” constitutes the most unbearable realistic picture for many ordinary people in rural areas when facing cancer.