Cancer that originates in the lungs (primary lung cancer) may be confined to the airways within the lungs, as the airways are blocked and air cannot enter the lungs. This cancer may also spread to other parts of the body. This can lead to lung cancer.
In the United States, primary lung cancer is a leading cause of cancer death in both men and women, with 85% of lung cancer cases being caused by smoking.
The risk of developing cancer increases with the number of cigarettes a person smokes over their lifetime. For someone who has smoked for 40 years and smokes more than a pack a day, the risk of lung cancer is very high. While cigar smokers do not have as high a risk of cancer as cigarette smokers, their risk is still significantly higher than that of non-smokers.
In addition to smoking, other factors that can lead to lung cancer include exposure to asbestos, radon, and uranium. Lung damage from interstitial lung disease and chronic infections, such as tuberculosis, also increases the risk of primary lung cancer.
The outlook for lung cancer patients is not optimistic. Approximately 85% of lung cancer patients will die within five years of being diagnosed. For patients whose tumors are confined to one location (with no signs of spreading to the lymph nodes in the chest), surgery can extend the life of 60% of these patients. However, most cancers are not detected until they have spread.
Lung cancer can be effectively prevented for those who never smoke or who quit smoking as soon as possible. Once you quit, your risk of lung cancer will gradually decrease. If you have quit for 15 years or more, your risk of lung cancer will be close to that of someone who has never smoked.