According to the American Lung Association, lung cancer causes an estimated 157,200 deaths annually, more than the next three most common cancers combined - breast, prostate and colon.
Cancer that begins in the lungs can be divided into two major types:  non-small cell lung cancer and small cell lung cancer, depending on how the cells look under a microscope.  Each type of lung cancer grows and spreads in different ways and is treated differently:

• Non-small cell lung cancer -- This is more common than small cell lung cancer, and it generally grows and spreads more slowly.  There are three main types of non-small cell lung cancer:  squamos cell carcinoma, adenocarcinoma and large cell carcinoma. 
  
  
• Small cell lung cancer -- This cancer is considered to be less common than non-small cell lung cancer.  This type of lung cancer grows more quickly and is more likely to spread to other organs in the body. 

Two other thoracic malignancies treated at the USC/Norris Lung Cancer Program are:

• Malignant mesothelioma - This is an asbestos-related disease that is relatively uncommon but no longer rare.  A layer of specialized cells called the mesothelial cells line the chest cavity, abdominal cavity and the cavity around the heart.  The tissue formed by these cells is called mesothelium.  A malignant tumor of the mesothelium is called malignant mesothelioma.  Customized treatment depends on the size of the cancer, where the cancer is located, how far the cancer has spread, how the cancer cells look under the microscope, how the cancer responds to treatment, as well as the patient's age. 
  
  
• Thymoma -- This is a disease in which cancer cells are found in the tissues of the thymus, a small organ that lies under the breastbone.  It makes white blood cells called lymphocytes that travel through the body and fight infection.  Thymoma is usually a slow-growing tumor that does not spread beyond the thymus.  People with thymoma often have other diseases of the immune system, most commonly myasthenia gravis, a disease in which the muscles become weak.