Lung Cancer Causes and Risk Factors

Explaining why one person develops lung cancer and why another does not is a challenging task for doctors. While it may be difficult to pinpoint the exact underlying cause of lung cancer, research has determined certain elements that are known to elevate the likelihood of becoming afflicted. Doctors call these elements risk factors.

The American Cancer Society, the Centers for Disease Control and Prevention and the National Cancer Institute all list cigarette smoking as the No. 1 cause of lung cancer in the United States. Inhaling secondhand smoke, or the cigarette smoke of others, increases the chance of developing lung cancer as well.

Things that may be present at home or in the workplace like asbestos, radon gas or other carcinogens can also increase your risk. Even personal traits that you cannot control can affect your cancer risk. For example, having a personal or family history of lung cancer significantly increases your likelihood of getting the disease, too. Lastly, diet has been shown to affect cancer risk, but much more research needs to be done before any associations can be called conclusive.

Risk Factors

A risk factor can be anything that increases the chance of developing a disease like lung cancer. However, risk factors are not always definitive. For example, some patients develop lung cancer without having any risk factors at all. Likewise, exposure to multiple risk factors will not always result in the disease in many cases. Studies have found the following to be the most common risk factors for lung cancer:

Smoking and Secondhand Smoke

Smoking harms nearly every organ in the body and negatively affects a person's overall health. Causing nearly 90 percent of all diagnosed lung cancer cases, cigarette smoke is by far the leading risk factor for the disease. The longer a person has been smoking and the more packs a day he or she smokes typically magnifies the risk involved, although some are more prone to the cancer-causing effects of tobacco than others. According to the American Cancer Society, quitting smoking at any age, regardless of smoking history, can lower the risk of lung cancer while giving damaged lung tissue the chance to repair itself over time. About 15 years after quitting, a former smoker's risk of developing lung cancer begins to approach that of a lifetime nonsmoker.

People who do not smoke are equally susceptible to the dangers of cigarette smoke if inhaled. For example, the U.S. Surgeon General estimates that nonsmokers living with a smoker experience a 20 to 30 percent greater risk of developing lung cancer. Exposure to smoke in the workplace also increases the overall likelihood of contracting the disease. About 3,000 nonsmoker deaths are attributed to secondhand smoke annually.

Asbestos

Exposure to asbestos has been linked to the development of several serious health conditions including lung cancer, mesothelioma and asbestosis. A naturally occurring mineral found in homes, at the workplace or in the environment, asbestos has been mined and used for a variety of commercial purposes in North America since the late 1800s. Today, asbestos use is highly regulated, as it is classified as a known human carcinogen by the U.S. Department of Health and Human Services, the U.S. Environmental Protection Agency (EPA) and the International Agency for Research on Cancer.

When products containing asbestos are disturbed, microscopic asbestos fibers are released into the air. These fibers, if inhaled, can become trapped in the lungs and accumulate over long periods of time causing inflammation, scarring and critical health problems. Asbestos exposure is a risk factor for lung cancer, and the risk is dramatically increased if the person affected is also a smoker.

Asbestos exposure also increases the chance of developing mesothelioma, a rare cancer that starts in the soft lining that surrounds the lungs or abdomen. Although mesothelioma can be difficult to treat, an early diagnosis and aggressive treatment can greatly improve the patient's outlook. For more information about mesothelioma, treatment options and referrals to top doctors, click here to receive a complimentary informational packet from the Mesothelioma Center.

Radon Gas

Radon is an odorless, cancer-causing gas that is estimated to cause about 21,000 lung cancer deaths per year. Forming from the natural breakdown of uranium in soil and rocks, radon decays into radioactive particles that can accumulate in homes and become trapped in the lungs when inhaled. This can damage lung tissue and greatly increase the risk of developing lung cancer. Only smoking causes more lung cancer-related deaths according to the EPA, and the risks associated with radon are especially high for smokers. The U.S. Surgeon General and the EPA highly encourage homeowners to test for radon. Discount test kits can be obtained by contacting the National Safety Council's radon hotline at
(800) 767-7236.

Workplace Carcinogens

In addition to asbestos, several other carcinogens can be found at the workplace that increase the risk of lung cancer, especially for those who work in the construction and chemical industries. Other risk factors include:

• Exposure to radioactive ores like uranium
• Exposure to arsenic
• Inhalation of chemicals such as beryllium, cadmium, chloromethyl ethers, chromium compounds, coal products, nickel compounds and vinyl chlorides

As with many other lung cancer risk factors, asbestos exposure for smokers has what is called a synergistic effect. This means that the actual risk of getting lung cancer is much higher than the individual risk factors combined. If you are a smoker and suspect exposure to any workplace carcinogens, especially asbestos, you should quit smoking immediately and contact your doctor.

Personal/Family History

Although the majority of lung cancers are caused by smoking, the fact that not every smoker develops cancer suggests that other factors play an important role in susceptibility to the disease. A recent study by the International Agency for Research on Cancer (IARC) involving 10,000 subjects from 18 countries identified genes that appear to increase lung cancer risk in some smokers. Further research is currently underway to better understand the connections between lung cancer risk and individual genetics.

If you have had lung cancer in the past, you have a higher risk of developing another lung cancer tumor. A person's risk may also be higher if his or her parents, siblings or children were diagnosed with the disease. This increased risk can be explained by several things. Families could share a risky behavior like smoking, or they may live in the same place where there are carcinogens like radon gas. Elevated risk could also be inherited genetically. Again, more research is still being done on this topic.

Diet

The possible effects of diet on lung cancer risk remains a controversial topic, but it is of great interest to researchers. Initial dietary studies were few and inconsistent, but more recent endeavors have reached notable conclusions while laying the groundwork for future research. Hawaii has been the setting for many diet-related studies, 13 of which indicated that high dietary cholesterol and excessive consumption of alcohol can lead to an increased risk of lung cancer. Some foods are suspected to actually help prevent lung cancer as well, although more research must be done before the evidence can be called conclusive. However, preliminary studies have linked vitamin A to a decreased risk of lung cancer.

Confronting Your Risk Factors

The best way to prevent lung cancer is to avoid smoking. If you are a smoker, you should ask your healthcare provider to assist you in quitting as soon as possible. If you suspect that you have been exposed to radon, asbestos or any other carcinogens linked to lung cancer, you should contact a doctor immediately and take steps to lower any risk factors that you can control. If you need assistance with finding a qualified doctor and treatment facility near you, click here to visit the Mesothelioma Center's Doctor Match Program or call us at (800) 549-0544.

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