According to the location of the tumor, the pathology of lung cancer can be divided into: (1) Central type: the tumor occurs in the bronchus above the opening of the segmental bronchus. (2) Peripheral type: the tumor occurs in the bronchus below the opening of the segmental bronchus. Histological classification of lung cancer is divided into: (1) squamous cell carcinoma: referred to as squamous carcinoma, accounting for about 30%-35% of all lung cancers, squamous carcinoma is mainly central type lung cancer, peripheral type squamous carcinoma is less common. (2) Adenocarcinoma: about 35%-40%, including three subtypes of adenocarcinoma: alveolar adenocarcinoma, papillary adenocarcinoma, and bronchioalveolar cell carcinoma. Adenocarcinoma can be either central or peripheral type, but the latter is slightly more common. (3) Large cell carcinoma: accounting for about 10% of the cases, including two subtypes of giant cell carcinoma and clear cell carcinoma. (4) Adenosquamous carcinoma: It is a kind of carcinoma with both squamous and adenocarcinoma components. (5) Small cell carcinoma: accounting for 20%-25%, including three subtypes of oat cell carcinoma, intermediate cell carcinoma and mixed oat cell carcinoma. The biological characteristics of this type of lung cancer are high malignancy and easy metastasis. (6) Other types of lung cancer include bronchial adenocarcinoma, carcinoid tumor, carcinosarcoma, etc., which are less common. 3.According to the biological characteristics of lung cancer and different treatment methods, lung cancer is divided into two categories: (1) small cell lung cancer: accounting for 20%-25% of all lung cancers, the treatment needs to be a combination of chemotherapy-based treatment. (2) Non-small cell lung cancer: all types of lung cancer except small cell lung cancer, accounting for 75%-80% of all lung cancers. The treatment mostly adopts a comprehensive approach based on surgical treatment.