Primary lung cancer (PLC) is the most common malignant tumor in the world. PLC is generally divided into two major groups based on pathology and treatment: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC accounts for 80%−85% and the rest is SCLC. Because of the unique biological behavior of SCLC, the combination of chemotherapy and radiotherapy is mainly used, in addition to a few early cases. If not specified, lung cancer is always regarded as NSCLC.
Lung cancer is the fastest growing malignant tumor in China in recent 30 years. According to the data of the first death causes retrospective survey conducted in the mid-1970s, the mortality of lung cancer in China was 5.47/100,000, ranking fifth in cancer death, following gastric cancer, esophageal cancer, liver cancer and cervical cancer, accounting for 7.43% of all cancer deaths. The results of the second sampling survey of causes of death in China showed that in the 1990s, lung cancer was the third leading cause of death for cancer, only second to gastric cancer and esophageal cancer. The third retrospective survey of death causes conducted in this century shows that lung cancer has become the leading cause of cancer death. According to the latest statistics from the National Cancer Registry, there were about 650,000 new cases of lung cancer in China in 2011, and 520,000 patients died due to lung cancer, and both ranked first in malignant tumors. According to data released by the National Cancer Registry in 2016, there were 733,300 new cases of lung cancer in China (5,093,200 males and 224,000 females) in 2015, ranking first in malignant tumors (the first in males and the second in females), accounting for 17.09% of new cases in malignant tumors (20.27% for males and 12.59% for females). In the same period, the number of lung cancer deaths in China was 610,200 (43,224 males and 177,800 females), accounting for 21.68% of the causes of malignant tumors (23.89% for males and 17.70% for females). In terms of regional distribution, the mortality of lung cancer in urban areas in China is higher than that in rural areas. The mortality rate of lung cancer in urban and rural areas in east and central China was significantly higher than that in western China. The age of morbidity increased rapidly in the group of more than 40 years.