Lung cancer is divided into two major pathological types: small cell lung cancer and non-small cell lung cancer. The prognosis of small cell lung cancer is relatively poor, and distant metastases, such as bone metastases and brain metastases, are often detected early. 5-year survival rate, if not operated, is less than 10%. Small cell lung cancer tends to have less chance of surgery, and the 5-year survival rate for early stage small cell lung cancer is around 30%-40%. The prognosis of non-small cell lung cancer, mainly adenocarcinoma and squamous carcinoma, is relatively good, as squamous carcinoma tends to have late metastasis, while adenocarcinoma has early distant metastasis. Of course, with the development of genetic drugs and immunosuppressive drugs, both small cell lung cancer and non-small cell lung cancer have significantly richer treatment options and longer survival periods.