Cancer continues to be a leading cause of death worldwide. According to data published by the World Health Organization, there were 7.6 million cancer deaths in 2008 (about 13% of all deaths). The major types of cancer include: lung cancer (1.37 million deaths), stomach cancer (736,000 deaths), liver cancer (695,000 deaths), colorectal cancer (608,000 deaths), breast cancer (458,000 deaths), and cervical cancer (275,000 deaths). Approximately 70% of all cancer deaths occur in low- and middle-income countries, and the number of cancer deaths worldwide is expected to continue to rise, exceeding 13.1 million by 2030. Another WHO projection indicates that without intervention, 84 million people will die of cancer worldwide between 2005 and 2015. According to the data published by WHO, 161 million people were diagnosed with lung cancer in 2008, accounting for 13% of the total number of cancer cases worldwide and ranking first, with 55% of them in developing countries. The incidence of lung cancer in men is 2.5 times higher than that of women worldwide, but the incidence of lung cancer in men varies by regions up to 20 times, with the highest incidence in Central and Eastern Europe in 2008 in Russia, Ukraine, and Belarus at 57 per 100,000 people. The incidence of lung cancer in Asia is 32.4 per 100,000 for men, the highest of all male tumors, and 22.3 per 100,000 for women. The age-standardized mortality rate for lung cancer is increasing yearly at a rate of 1-5% per year, and it is also increasing rapidly in women. This trend is especially obvious in developing countries, but in developed countries in Europe and America (except France and Japan) this trend is leveling off or even decreasing.2. The epidemiological trend of lung cancer in China In recent years, the composition of the top 10 malignant tumors in urban and rural areas in China, lung cancer has replaced liver cancer as the first cause of death from malignant tumors in China, accounting for 22.7% of all malignant tumor deaths. And the incidence rate and mortality rate continue to rise rapidly. According to the information provided by the National Cancer Control Office of the Ministry of Health, the number of lung cancer cases in China is estimated to increase by 120,000 between 2000 and 2005, among which, the number of male lung cancer patients increased from 260,000 in 2000 to 330,000 in 2005, and the number of female lung cancer patients increased from 120,000 to 170,000 in the same period. Currently, the incidence of lung cancer in China is increasing by 26.9% per year, and if effective control measures are not taken in time, it is expected that by 2025, China will reach 1 million lung cancer patients and become the world’s number one lung cancer country.3. Survival rate of lung cancer According to SEER (Surveillance, Epidemiology, and End Results) in the United States According to the SEER (Surveillance, Epidemiology, and End Results) in the United States, the 5-year survival rate after diagnosis of lung cancer was 12.7% from 1975 to 1977 and 15.7% from 1996 to 2004, while the 5-year survival rate after diagnosis of lung cancer in Europe was 8-12% and 5-12% in developing countries. In general, the survival rate of female lung cancer is higher than that of male lung cancer, and non-small cell lung cancer is higher than small cell lung cancer.4. Etiology of lung cancer Nowadays, research recognizes that the main causes of lung cancer are smoking, environmental pollution and radon exposure. Some data show that the incidence of lung cancer in long-term smokers is 10 to 20 times higher than that of non-smokers. 85% to 90% of lung cancer cases in the United States are smokers, while smoking is equally common in other countries. Although various countries have taken action to control tobacco, including measures such as banning smoking in public places and banning tobacco-related advertising from appearing in the media. However, the smoking population continues to expand worldwide, with 1.3 billion smokers worldwide, 900 million in developing countries, an increase in the number of young people smoking, a decrease in the age of first smoking, and an increase in the number of women smoking. While the number of smokers is increasing, the number of passive smokers is also expanding. In 2004, air pollution caused 165,000 lung cancer deaths worldwide, of which: 108,000 were caused by outdoor air pollution; 36,000 were caused by the use of solid fuels Cooking and heating caused cancer; 21,000 patients were caused by second-hand smoke. Radon exposure is also gradually becoming the main cause of lung cancer. It is estimated that 3% to 14% of the total number of lung cancer patients in 2004 were caused by indoor radon exposure, which is also the second leading cause of lung cancer in many countries. The proportion of lung cancer caused by radon is expected to be in the range of 3% to 14%. For every 100 Bq/m3 increase in radon concentration, the risk of lung cancer increases by 16%, and radon is more likely to make smokers suffer from lung cancer.