Emphysema and lung cancer can occur together.
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Globally, lung cancer is the most common cancer in men and the second most common cancer in women. Lung cancer is also the most common cause of cancer-related death worldwide. In the United States, trends in lung cancer tend to follow trends in cigarette smoking. Emphysema, another smoking-related disorder, is characterized by lung tissue destruction and over-expansion of the lung's air spaces. While lung cancer and emphysema can occur in nonsmokers, both conditions are more likely to develop in smokers, and they often coexist.
Progressive Tissue Damage
In the 2011 issue of Critical Reviews in Biomedical Engineering, scientists at Boston General Hospital and Harvard Medical School reported that emphysema results from the interplay of several factors. Oxidative stress from inhaled irritants causes tissue damage, which triggers inflammation. An imbalance between repair and remodeling mechanisms perpetuates the damage. Air trapping, mucus pooling and the mechanical forces of breathing place additional stresses on already-injured tissues, and they eventually begin to break down. Many of these same factors may contribute to the development of lung cancer.
According to a 2012 review in The Journal of Clinical Investigation, cigarette smoke contains thousands of chemicals that injure your lungs in various ways. Heavy metals, oxidizing agents, nicotine and cancer-promoting substances all play a role in the genesis of emphysema and, in some people, lung cancer. Because lung cancer also occurs in nonsmokers, other environmental, occupational and genetic factors may be involved, but these factors have not all been identified. Smokers have served as the primary research model for lung cancer and emphysema, as both diseases are far more prevalent in this group.
Establishing the Link
Many studies have shown an association between emphysema and lung cancer, but most of these studies used subjects whose emphysema was diagnosed on the basis of symptoms, smoking history and physical examination. A study conducted at Mayo Clinic in Rochester, Minnesota, and published in the January 2011 issue of Cancer Prevention Research demonstrated that people with CT-confirmed emphysema were, in fact, at higher risk for lung cancer. Furthermore, this risk was highest for young people and for heavy smokers. Having emphysema may boost your risk for lung cancer by three to four times.
Is Screening Recommended?
Since it is not only possible, but more likely, to develop lung cancer if you already have emphysema, it may soon become routine to perform lung-cancer screening in people who have or are at risk for emphysema. According to a 2012 survey in Annals of Family Medicine, many primary care physicians in the U.S. already order lung cancer screens.
Several expert panels, including the American Cancer Society and the American College of Chest Physicians, believe lung cancer screening may be beneficial for certain individuals, but no consensus has been reached on how such screening should be implemented. Smokers, people who are exposed to secondhand smoke and individuals with occupational exposure to dusts and fumes may benefit most from screening, which is best accomplished with chest CT. Your doctor can determine if you are a candidate for screening.