introduction
Lung cancer is the most common form of cancer and causes more deaths worldwide than any other cancer. In the United States, lung cancer is the primary cause of cancer death among both men and women, killing 160,390 people in 2007, which exceeds the combined mortality attributable to breast, prostate and colon cancer. In 2007 there were 213,380 new cases of lung cancer diagnosed in the United States: 114,760 among men and 98,620 among women. On average, 1 in 13 men and 1 in 16 women will be diagnosed with lung cancer (a lifetime risk of 8% and 6%, respectively).
The single most important factor influencing the risk of developing lung cancer is smoking. In the United States, smoking is estimated to account for 87% of lung cancer cases (90% in men and 85% in women). The lifetime risk of developing lung cancer is 17.2% among male smokers and 11.6% among female smokers. This risk is significantly lower in non-smokers: 1.3% in men and 1.4% in women.
Epidemiological studies have shown that genetic factors also contribute to the risk of developing lung cancer.
Recently scientists at deCODE genetics discovered an association between the diagnosis of Lung cancer and a specific variant in the genome. The variant is located on chromosome 15 within the nicotinic acetylcholine receptor gene cluster. In smokers, this same variant also increases the risk for Nicotine Dependence and Peripheral arterial disease.
The deCODEme Genetic Scan identifies the risk variant rs1051730 on chromosome 15 and provides an interpretation of the associated risk for developing lung cancer for individuals of European descent who smoke. More studies need to be conducted to test if the variant also increases risk of lung cancer in people who do not smoke. Currently no data are available for people of other ethnicities for this variant.
risk factors
- Smoking: Smoking is the greatest known risk factor for lung cancer and is estimated to be responsible for approximately 90% of lung cancer in men and 85% in women. Lung cancer risk attributable to tobacco smoking is strongly affected by the duration of smoking, and declines with increasing time from cessation. Thus, the estimated lifetime risk of lung cancer among former smokers ranges from approximately 6% in smokers who give up at the age of 50, to 10% for smokers who give up at age 60, compared to 15% for lifelong smokers and approximately 1% in never-smokers.
- Secondary smoke: Secondary smoke is estimated to cause approximately 3,000 lung cancer deaths per year among non-smokers and contributes to more than 35,000 deaths linked to cardiovascular disease.
- Genetics: Regardless of exposure to tobacco smoke, there are important individual differences in the risk of developing lung cancer, some of which are attributable to genetic factors. Thus, for example, even though smoking is the primary cause of lung cancer, only about 15% of lifelong smokers will actually develop this disease. Genetic factors may influence who end up developing the disease. The role of genetics is further demonstrated by the fact that close relatives of lung cancer patients have an approximately two-fold greater risk of developing the disease compared to the general population.
- Environmental pollutants: Exposure to a variety of environmental factors or industrial substances has been associated with increased risk of lung cancer. These include asbestos, radon and arsenic. Certain lung diseases can also increase the risk for lung cancer. However, these factors combined still contribute much less to the disease risk than tobacco smoking.
more information
You can find out more information about lung
cancer and smoking by talking to your doctor and visiting these Web sites:
Centers for Disease Control and Prevention
on Smoking and Nicotine Dependence
Lung Cancer.org, A Program of Cancer Care
National Cancer
Institute on Lung Cancer