Lung cancer often starts quietly, but it gives out clear warning signs once a tumor begins to block airways or irritate nearby nerves. Knowing what to watch for can lead to earlier testing and better odds of successful treatment. A cough that won’t go away is the most common first clue. It may sound like your usual smoker’s hack at first, then turn deeper or more frequent. Coughing up blood—bright red or rust-colored spit—is a red flag that needs immediate attention. Chest pain that feels like a dull ache or a tight band when you breathe deeply or laugh can... Learn more