Patients with early-stage lung cancer generally do not experience facial swelling. This is because early-stage lung cancers mainly include carcinoma in situ and stage I lung cancer. At this stage, the cancer tissue is confined to the mucosa, without invasion of the surrounding tissues or distant metastasis. Therefore, the clinical symptoms of patients with early-stage lung cancer primarily involve the respiratory system. Clinical symptoms mainly include coughing, often a dry cough without phlegm, or coughing up phlegm with blood, hemoptysis, and massive hemoptysis. Some patients may experience chest pain, or have a barking cough, or a metallic-sounding cough. Some patients may have shortness of breath after physical activity, and severe cases can experience breathing difficulties. In most cases, patients do not exhibit other clinical changes. However, as the disease progresses, and there is invasion into surrounding tissues, or distant metastases occur, symptoms of invasion into surrounding tissues or distant metastatic sites may appear. For example, metastasis to the cervical lymph nodes can cause enlarged lymph nodes, or compression of the superior vena cava by the patient, resulting in swelling of the face and neck.