Lung cancer is a type of cancer that begins in the lungs. If left
untreated, it can spread beyond the lungs into nearby tissue or other
parts of the body. Smoking is the main cause of lung cancer. Smoking is the single main avoidable cause of lung cancer. It is not
known why one smoker develops lung cancer and another does not. Up to
90% of lung cancer is caused by smoking.
Lung cancer occurs most often in adults between the ages of 40 and 70 who have smoked cigarettes for at least 20 years. They are also likely to have started smoking as teenagers. Second-hand smoking (passive smoking) may also cause lung cancer. However, as with many cancers, we do not know the cause in all cases.
http://www.healthnavigator.org.nz/health-a-z/l/lung-cancer/
Lung cancer occurs most often in adults between the ages of 40 and 70 who have smoked cigarettes for at least 20 years. They are also likely to have started smoking as teenagers. Second-hand smoking (passive smoking) may also cause lung cancer. However, as with many cancers, we do not know the cause in all cases.
http://www.healthnavigator.org.nz/health-a-z/l/lung-cancer/