Non-Small Cell Lung Cancer - Risk Factors

In China, it is estimated that as many as a third of all young male smokers will eventually die because of a tobacco-related illnesses. Their risk for lung cancer, however, is much less than for chronic lung disease, a trend that is reversed in the West. A 2001 study reported that the lower rate of lung cancer among Chinese people may be due to a slow rate clearing nicotine, which results in fewer cigarettes smoked.

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Environmental Factors

People with High Exposure to Radon. Studies have shown that radon raises the risk of lung cancer in underground miners to 40%. It has been unclear whether the results of these studies would apply to people exposed to radon in their homes. One study suggests that people with intense or prolonged exposure to radon in their homes do indeed face the same risk as miners exposed to similar levels of radon. A cumulative long-term exposure to radon and smoking also increases the danger. Most people move an average of 10 or 11 times over their lifetime, so the risk of developing lung cancer through radon exposure is very low in most individuals, even for those who lived for awhile in areas with high radon levels. People with homes that have high radon levels and those who sleep or spend many hours to days in basements with detectable but moderate levels should consider taking protective measures.

Workers Highly Exposed to Carcinogens. An estimated 9,000 to 10,000 men and 900 to 1,900 women develop lung cancer each year because of occupational exposure to carcinogens. More than half of these cases are attributable to past exposure to asbestos, which has long been known to be a risk factor for mesothelioma (cancer of the pleura, the lining around the lung) and can increase the risk of lung cancer in smokers. With better protective measures, these rates are expected to fall in the future.

Other chemicals that put workers at risk for lung cancer include:

Arsenic (insecticide and herbicide sprayers, tanners, oil refinery workers).
Chloromethyl methyl ether (workers exposed to certain polymers, water repellents, or products using chloride and formaldehyde).
Chromium compounds (workers using certain alloys, paints, pigments, and preservatives).
Depleted uranium (soldiers exposed to weapons during battlefield conditions).
Crystalline silica.

By contrast, agricultural workers seem to have a lower lung cancer rate, despite their possible occupational exposures to risky chemicals. While this rate has traditionally been attributed to good health habits, including low tobacco use, a 2000 study suggests that agricultural workers' exposure to endotoxin may be responsible. Endotoxin is a component of common bacteria found in soil and animals and may have cancer-preventing effects on the immune system.