Lung Cancer

What Is Lung Cancer?

Lung cancer is the leading cause of cancer death in both men and women. Lung cancer is a cancer that usually starts in the lining of the bronchi (the medium-sized airways within lungs), but can also begin in other areas of your respiratory system, including the trachea (main breathing tube), bronchioles (smaller branches of the air passages), or alveoli (the tissue farther out in the periphery of the lung).

Lung cancers are believed to develop over a period of many months to years. Nearly all lung cancers are "carcinomas"—tumors that begin in the lining or covering tissues of an organ. The tumor cells of each type of lung cancer grow and spread differently, and the treatments of these various types differ to some extent. About 85-90% of lung cancers belong to the group called non-small cell lung cancer.

Causes of lung cancer

A risk factor is anything that increases your chance of getting a disease such as cancer. Different cancers have different risk factors. Several risk factors make a person more likely to develop lung cancer:

• Smoking is the leading cause of lung cancer, with nearly 90% of lung cancer deaths thought to be a result of smoking, although approximately 20% of women with lung cancer have never smoked. Most non-smokers who get lung cancer are of Asian ancestry, are women, or both. These tumors often contain a specific EGFR gene mutation, which makes them treatable with targeted therapy drugs, taken in pill form.

Additional risk factors include:

• Secondhand smoke (breathing in the smoke of others)
• Asbestos exposure
• Cancer-causing agents in the workplace, including:
  • Radioactive ores such as uranium
  • Arsenic
  • Vinyl chloride
  • Chromates
  • Coal products
  • Mustard gas
  • Chloromethyl ethers
• Radon: A radioactive gas that cannot been seen, tasted, or smelled. It is produced by the natural breakdown of uranium. High levels of radon may be found in some homes or other buildings, especially in basements.
• Personal or family history of lung cancer
• Air pollution: In some cities, air pollution may slightly increase the risk of lung cancer.