Lung diseases are medical disorders that affect the lungs. The Us Dept. of Health and Human Services considers lung diseases to be serious problems because breathing problems may prevent the body from getting the oxygen it needs to stay healthy. Lung disorders are common problems, and lifestyle issues such as smoking and environmental issues have contributed to the debate and discussion about lung disease over the last 20 years. Second Opinion doctors and patients have addressed some of the most common lung diseases, including asthma, COPD and lung cancer, which is one of the most frequently diagnosed cancers in America.