Lung cancer occurs in the bronchial mucosa epithelium and is also called bronchopulmonary cancer. Lung cancer generally refers to cancers of the parenchyma of the lung and usually does not include other tumors such as mesothelioma of cribriform origin, or other malignant tumors such as carcinoid, malignant lymphoma, or tumors that metastasize from other sources. Therefore, when we refer to lung cancer, we mean malignant tumors from bronchial or bronchiolar epithelial cells, which account for 90-95% of all malignant tumors of the lung parenchyma. Lung cancer is currently the number one cause of cancer deaths worldwide, with 600,000 deaths worldwide in 1995, and the number is increasing every year. The incidence of lung cancer in women in particular is on the rise. Lung cancer originating from the mucosal epithelium of the bronchi confined to the basement membrane is called carcinoma in situ, which can grow into the bronchial lumen or/and adjacent lung tissues and can spread through lymphatic bloodstream or transbronchial metastasis. The growth rate and metastatic spread of carcinoma are related to the biological characteristics of the carcinoma such as histological type and degree of differentiation. The distribution of lung cancer is more in the right lung than in the left lung, more in the upper lobe than in the lower lobe, and the cancer can occur from the main bronchus to the fine bronchus. Lung cancers originating from the main bronchus and lobe bronchi are located close to the hilum and are called central lung cancers; lung cancers originating below the bronchi of the lung segment and located in the peripheral part of the lung are called peripheral lung cancers.