Healthy Lung and Lung Cancer
Secondhand smoke, also known as environmental tobacco smoke, causes approximately 3,400 lung cancer deaths and between 22,000-70,000 heart disease deaths in adult nonsmokers in the US per year. Lung cancer is the most common cause of cancer-related death in men and the second most common in women. It is no coincidence that over 90% of lung cancer patients are smokers. Normally, the little hairs (cilia) and mucus that line the respiratory track are effective at preventing damaging or abrasive materials from making it into the lungs. The lung on the left side of this image is healthy and has all its natural biological barriers intact. Tobacco smoke destroys the precious cilia so that these protective structures are no longer on the job. Harmful irritants enter the respiratory tract, triggering mucus production but without the cilia, mucus is not able to mobilize along the respiratory tract and is unable to leave the body. Piles of mucus containing trapped inhaled materials can lead to serious lung diseases including cancer. The lung pictured on the right side of the image has developed the hollowed out spaces characteristic of squamous cell carcinoma.