The pathological histological typing of lung cancer can be divided into two main categories according to the morphology of cancer cells – small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Small cell lung cancer has smaller cancer cells with the morphology of oat grains, also known as oat cell cancer. As the name suggests, non-small cell lung cancer is lung cancer other than small cells. Non-small cell lung cancer can be further subdivided into various types, such as adenocarcinoma, squamous carcinoma, adenosquamous carcinoma, large cell carcinoma, and sarcomatoid carcinoma. It is important to clarify the pathologic histologic typing of lung cancer because there are significant differences in the developmental characteristics, treatment and prognosis of different types of lung cancer. Non-small cell lung cancer and small cell lung cancer are different in the following aspects: 1. Etiology Non-small cell lung cancer is related to smoking, air pollution, occupational exposure and other factors, while small cell lung cancer is mostly related to lung cancer smoking factors. Non-small cell lung cancer is relatively slow to spread, while small cell lung cancer is fast growing, aggressive and early to metastasize distantly. 3.Symptoms Non-small cell lung cancer mostly focuses on local symptoms of lung, while small cell lung cancer can show obvious systemic symptoms. 4.Treatment Non-small cell lung cancer can be treated by surgery, radiotherapy, targeted therapy, immunotherapy, etc. depending on the stage, while small cell lung cancer is mostly sensitive to radiotherapy, and the effect of surgery is limited because of metastasis when diagnosed. 5.Prognosis If non-small cell lung cancer can be detected and treated in time, it can achieve better treatment effect, and the treatment effect of late stage non-small cell lung cancer is better than small cell lung cancer. Small cell lung cancer, on the other hand, has a relatively poor prognosis because it is more difficult to be detected early and has fewer treatment means.