Why Non-smokers Sometimes Get Lung CancerNov 1, 2016
As many as 20% of the people who die from lung cancer in the United States every year do not smoke or use any other form of tobacco. This translates to about 16,000 to 24,000 Americans every year. In fact, if lung cancer in non-smokers had its own separate category, it would rank among the top 10 fatal cancers in the United States.
It’s still true that staying away from tobacco is the most important thing any of us can do to lower our risk of getting lung cancer. But there are also other risk factors. Researchers have made a lot of progress over the past decade in understanding what causes lung cancer in non-smokers:
- Radon gas. The leading cause of lung cancer in non-smokers is exposure to radon gas, according to the US Environmental Protection Agency (EPA). It accounts for about 21,000 deaths from lung cancer each year. Radon occurs naturally outdoors in harmless amounts, but sometimes becomes concentrated in homes built on soil with natural uranium deposits. Studies have found that the risk of lung cancer is higher in those who have lived for many years in a radon-contaminated house. Because radon gas can’t be seen or smelled, the only way to know whether it’s a problem in your home is to test for it. A Citizen’s Guide to Radon, produced by the EPA, explains how to test your home for radon easily and inexpensively, as well as what to do if your levels are too high.
- Secondhand smoke. Each year, an estimated 7,330 adults die of lung cancer as a result of breathing secondhand smoke. Laws that ban smoking in public places have helped to reduce this danger. The American Cancer Society Cancer Action NetworkSM (ACS CAN), the nonprofit, nonpartisan advocacy affiliate of the American Cancer Society, is working to expand and strengthen these laws to further protect both smokers and non-smokers from the dangers of secondhand smoke.
- Cancer-causing agents at work. For some people, the workplace is a source of exposure to carcinogens like asbestos and diesel exhaust. Work-related exposure to such cancer-causing materials has decreased in recent years, as the government and industry have taken steps to help protect workers. But the dangers are still present, and if you work around these agents, you should be careful to limit your exposure whenever possible.
- Air pollution. It’s long been known that both indoor and outdoor air pollution contribute to lung cancer. In 2013, the World Health Organization (WHO) classified outdoor air pollution as a cancer causing agent (carcinogen). According to Elizabeth Ward, PhD, American Cancer Society National Vice President, Intramural Research, the risk of lung cancer associated with air pollution is lower in the US than in many other countries because of policies that have helped to lower the levels of exposure.
- Gene mutations. Researchers are learning more and more about what causes cells to become cancerous, and how lung cancer cells differ between non-smokers and smokers. For example, an article published in Clinical Cancer Research explains that a particular kind of gene mutation is much more common in lung cancer in non-smokers than smokers. This mutation activates a gene that normally helps cells grow and divide. The mutation causes the gene to be turned on constantly, so the lung cancer cells grow faster. Knowing which gene changes cause the cells to grow has helped researchers develop targeted therapies, drugs that specifically target these mutations.
Lifestyle changes to lower risk
Non-smokers have already eliminated their greatest risk factor for lung cancer. Male smokers are about 25 times more likely and female smokers are about 26 times more likely to get lung cancer than men and women who never smoked. But non-smokers can make some lifestyle changes to help reduce their risk even more.
Testing your home for radon, avoiding secondhand smoke, and limiting exposures at work can help you avoid the leading causes of lung cancer in non-smokers.
A healthy diet with lots of fruits and vegetables may also help reduce your risk of lung cancer. Some evidence suggests that a diet high in fruits and vegetables may help protect against lung cancer in both smokers and non-smokers. But any positive effect of fruits and vegetables on lung cancer risk would be much less than the increased risk from smoking.