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NIH MedlinePlus the Magazine, Trusted Health Information from the National Institutes of Health

Feature:
Lung Cancer

Understanding and Preventing Lung Cancer

Lung Cancer Diagram

Diagram of Stage 3A Cancer. Click for larger view.
©2010 Terese Winslow, U.S. Govt. has certain rights

What is Lung Cancer

Lung cancer forms in tissues of the lung, usually in the cells lining air passages. The two main types are small cell lung cancer and non-small cell lung cancer. These types are diagnosed based on how the cells look under a microscope.

  • Small cell: The cells of small cell lung cancer look small under a microscope. About 1 of every 8 people with lung cancer has small cell lung cancer.
  • Non-small cell: The cells of non-small cell lung cancer are larger than the cells of small cell lung cancer. Most (about 7 of every 8) people diagnosed with lung cancer have non-small cell lung cancer. It doesn't grow and spread as fast as small cell lung cancer, and it's treated differently.

Lung cancer is the leading cause of cancer death in both men and women. Lung cancer is the second most common cancer in the United States, after skin cancer. The number of new cases and deaths from lung cancer is highest in black men.

Risk Factors

Smoking is the main cause of lung cancer, especially non-small cell lung cancer. Exposure to secondhand smoke and environmental exposures, such as radon and workplace toxins, also increase your risk.

The earlier in life a person starts smoking, the more often a person smokes, and the more years a person smokes, the greater the risk of lung cancer. If a person has stopped smoking, the risk becomes lower as the years pass.

When smoking is combined with other risk factors—such as secondhand smoke, asbestos and arsenic exposure, and air pollution—the risk of lung cancer is increased. A family history of cancer can also be a risk factor for lung cancer.

Winter 2013 Issue: Volume 7 Number 4 Page 4