So, the early symptoms of lung cancer often include a cough, hemoptysis, difficulty breathing, and chest pain. However, these symptoms, particularly the irritating cough, typically appear after the tumor has grown in the larger bronchi; this is often mistaken for a cough following a cold, leading to misdiagnosis or delayed treatment. Therefore, if this type of irritating cough occurs, it is essential to seek medical attention promptly and to undergo chest X-ray or CT scan. Second, as the tumor continues to grow and affects the drainage of the bronchus, secondary lung infections may occur, often characterized by coughing up pus-like sputum, and an increase in the amount of sputum, which should also be noted. Third, a very common symptom is the presence of blood in the sputum, or streaks of blood, or intermittent minor hemoptysis, which must be taken seriously.