Lung cancer is divided into small cell lung cancer and non-small cell lung cancer according to pathological types, among which non-small cell lung cancer is divided into lung adenocarcinoma, lung squamous carcinoma and large cell lung cancer. The lower the degree of differentiation, the more malignant the lung cancer is, the faster it progresses and the faster it metastasizes. Squamous lung cancer occurs mostly in subsections of bronchi and larger bronchi, and is mostly central in nature, easily metastasizing to regional lymph nodes, easily developing cavities in the lungs, invading blood vessels and developing hemoptysis. Adenocarcinoma of the lung is most commonly seen in non-smokers or former smokers and is the most common type of pathology in female patients. Adenocarcinoma of the lung is usually a small peripheral lesion that is more likely to develop regional lymph nodes and distant metastases, but because the tumors are small and tend to appear peripheral, they often have no obvious symptoms. Large cell lung cancer is a lower percentage of lung cancers, but is more malignant than squamous lung cancer and adenocarcinoma of the lung. Small cell lung cancer and non-small cell lung cancer do not have exactly the same biological behavior. Small cell lung cancer is sensitive to chemotherapy and radiotherapy, but is more likely to recur.