Early-stage lung cancer, especially peripheral lung cancer, often has no symptoms and is mostly found during chest X-rays or CT scans. The clinical symptoms of lung cancer are closely related to the location, size, pathological type of the tumor, whether it compresses or invades adjacent organs, and whether there is metastasis. The symptoms of lung cancer generally include: First, some symptoms of the primary tumor growing locally, including cough, hemoptysis, difficulty breathing, and chest pain. When the tumor grows inside a larger bronchus, it might cause some irritative coughing. Second, as the tumor continues to grow and affects the drainage of the bronchi, it may lead to secondary lung infections, presenting with symptoms such as cough and purulent sputum. Third, there might be bloody sputum streaked with blood or intermittent minor hemoptysis, though significant hemoptysis is very rare.