What Causes Small Cell Lung Cancer?

This content has been reviewed and approved by

Chandra P. Belani, MD
Deputy Director, Penn State Cancer Institute
Miriam Beckner Professor of Medicine
Penn State University School of Medicine

Smoking is the leading cause of lung cancer. More than 90 percent of lung cancers are thought to be a result of smoking tobacco products. Like other types of cancer, lung cancer develops when your body rapidly produces unnecessary cells. Cancer typically forms along the airways of the lung and your windpipe.

Doctors and researchers believe there are certain factors that raise your chances of getting the disease. These are called risk factors for lung cancer. However, not everyone with a risk factor will develop cancer. Also, people without risk factors can develop the disease. Those who smoke cigarettes carry the highest risk factor.

Other Risk factors

Risk factors do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease even though they have no known risk factors. Different cancers have different risk factors. Several risk factors make a person more likely to develop lung cancer:

• Second-hand smoke - breathing in the smoke of others
• Smoking marijuana cigarettes, which:
  • Contain more tar than tobacco cigarettes.
  • Are inhaled very deeply.
  • Are smoked all the way to the end where tar content is the highest.
  • May contain fungi, pesticides, and other additives.
    
• Recurring inflammation, such as from tuberculosis and some types of pneumonia
• Asbestos exposure
• Cancer-causing agents in the workplace, including:
  • Radioactive ores such as uranium
  • Arsenic
  • Vinyl chloride
  • Nickel chromates
  • Coal products
  • Mustard gas
  • Chloromethyl ethers
  • Fuels such as gasoline
  • Diesel exhaust
• Radon - a radioactive gas that cannot be seen, tasted, or smelled; it is produced by the natural breakdown of uranium
• Personal history of lung cancer
• Air pollution - in some cities, air pollution may slightly increase the risk of lung cancer