Lung cancer is the second most common cancer in the United States, just behind prostate cancer in men and breast cancer in women. Lung cancer also happens to be the most lethal cancer, accounting for approximately 25% of all cancer deaths. Each year, more men die of lung cancer than from colorectal, prostate, and pancreatic cancers combined, and more women die annually of lung cancer than from breast, cervical, and uterine cancers combined.
The main risk factor for lung cancer is cigarette smoking, associated with 85% of cases. Among smokers, the risk of lung cancer increases with number of cigarettes smoked and duration of smoking history. There is good news though: the risk of lung cancer will decrease with smoking cessation and may even approach that of the nonsmoking population after 10 to 15 years of tobacco abstinence. Meanwhile, associated risks of developing lung cancer from e-cigarettes are currently under investigation.
Each year in the U.S., up to 26,0000 lung cancer deaths occur in never smokers, with an even higher proportion in some geographic areas. This brings us to environmental risk factors of lung cancer, such as exposure to radon, a chemically inert gas from uranium decay, encountered by underground miners and less commonly, residentially, through indoor exposure in the home basement. Asbestos exposure can lead to a type of lung cancer called mesothelioma and can cause other types of lung cancer when combined with smoking.
Arsenic, chromium, nickel, air pollution, and second-hand smoke represent other occupational or environmental exposures associated with lung cancer risk. Patients with treated for breast cancer, Hodgkin and non-Hodgkin lymphomas with high doses of radiation to the chest have increased risk of lung cancer, especially if they smoke cigarettes. Family history is another predictor of increased risk. Other diseases associated with increased lung cancer risk include chronic obstructive pulmonary disease and restrictive lung diseases, including fibrotic disorders like pneumoconiosis.
Finally, there have been dietary associations with lung cancer. An increased risk has been found with diets deficient in vitamins A and C, but supplementation with beta-carotene has been associated with an increased risk (in heavy smokers, the highest-risk populations, in 2 of 3 clinical trials).
On the basis of findings from the NLST trial, screening for lung cancer with low-dose computed tomography (LDCT) scan is recommended for certain patients by the U.S. Preventive Services Task Force (USPSTF). See Table 1.
Table 1. USPSTF Recommendation Summary for Lung Cancer Screening
| Population | Recommendation |
| Adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years | The USPSTF recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery. |
Adults aged 50 to 80 years have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years should screen for lung cancer with LDCT every year. A pack-year is a way of calculating how much a person has smoked in their lifetime. One pack-year is the equivalent of smoking an average of 20 cigarettes (1 pack) per day for a year. These recommendations are available at www.uspreventiveservicestaskforce.org.
If you would like to learn more and connect with a board-certified physician, click to book now on My Virtual Physician. My Virtual Physician offers comprehensive medical services where you can discuss the best screening plan for you with a virtual doctor.
References
https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/lung-cancer-screening
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Omenn GS, Goodman GE, Thornquist MD, et al: Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med 334:1150-1155, 1996. PMID: 8602180.
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Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group: The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med 330:1029-1035, 1994. PMID: 8127329
