Lung Cancer

Like all cancers, lung cancer is the result of in an uncontrolled growth of cells that eventually form a mass known as a tumor. Cancer can arise in any part of the lung, though 90 to 95% of cancers of the lung are thought to arise from the lining cells (epithelial tissue) of the lung's airways (bronchi and bronchioles). For this reason lung cancers are sometimes called bronchogenic carcinomas (1, 2).

Among bronchogenic carcinomas, there are two main categories: non-small cell lung cancers (NSCLC) and small cell lung cancers (SCLC). NSCLC are the most common type, accounting for about 80% of all lung cancers. SCLC comprise about 20% of lung cancers and are the more aggressive and rapidly growing of the two. Though uncommon, cancer can also arise from the thin layer of tissue that surrounds the lungs (the pleura), and in this case they are called mesotheliomas (2).

Survival rates for lung cancer are lower than those for most cancers, and lung cancer is the number one cause of cancer deaths in both men and women in the U.S. and worldwide. Part of the reason for this is because lung cancer tends to spread (metastasize) early in its development, and it is generally difficult to treat. While lung cancer can spread to any organ in the body, certain organs are common sites for lung cancer metastasis, especially the adrenal glands, liver, brain, and bones (2).

The lung is also a very common site for tumors to metastasize from other parts of the body. For example, renal cancer may spread via the bloodstream to the lungs; in this case, it is termed metastatic renal cancer in the lung, and not lung cancer.(2)

The incidence of lung cancer is strongly associated with cigarette smoking; about 90% of lung cancers are a result of tobacco use. Other causes can include the inhalation of asbestos fibers (particularly for mesotheliomas), exposure to radon gas, genetic predisposition, exposure to air pollution, and history of lung disease (especially prior lung cancer) (2, 3).

Diagnosis for lung cancer may involve a bronchoscopy, lung biopsy, thoracoscopy, mediastinoscopy. Treatment of lung cancer can involve a combination of surgery, chemotherapy, and radiation therapy as well as more recent experimental methods (2, 4).

'Lung Cancer' Sources:
  1. National Cancer Institute's website. Available: Lung Cancer (Accessed August 5, 2007).
  2. Stppler, M., M.D. "Lung Cancer."
  3. Cancer Research UK's website. Available: "Lung Cancer Risks and Causes." (Accessed August 5, 2007).
  4. Cancer Research UK's website. Available: "Lung Cancer Tests." (Accessed August 5, 2007).




 

 

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