Lung Cancer - Causes

By far the major cause of lung cancer is tobacco smoking. Ninety percent of all cases of lung cancer are thought to be caused by smoking. Other factors that may lead to lung cancer include:

• Exposure to asbestos and toxic chemicals. Asbestos is a naturally occurring mineral that was once used widely in many applications. For example, home and office insulation was once made of asbestos. Scientists now know that asbestos fibers can cause lung cancer. Studies show that people who work with asbestos are seven times more likely to die of lung cancer. A variety of other chemicals can also cause lung cancer, including arsenic, compounds of chromium and nickel, mustard gas, vinyl chloride, and emissions from coke ovens.
• Radon gas. Radon is a gas given off by radioactive materials. A radioactive material is a substance that gives off radiation and turns into a new substance. Radon gas is often formed in rocks that contain radioactive materials. It escapes from those rocks and gets into the air. It is often found in the basements of homes, office buildings, and factories built over such rocks. A person who smokes and is exposed to radon gas has the highest risk for lung cancer.
• Lung disorders. The lungs can be damaged by a variety of diseases and disorders. Among these are tuberculosis (see tuberculosis entry), pneumonia (see pneumonia entry), silicosis (pronounced sil-i-KO-siss), and berylliosis (pronounced buh-ril-ee-O-suhs). The last two diseases are caused by inhaling certain minerals. These diseases and disorders can scar lung tissue. Such scarring may later develop into tumors.
• Family history. People with relatives who have had lung cancer are at slightly higher risk for contracting (getting) lung cancer.