Lung cancer begins in the lungs and may spread to lymph nodes or other organs in the body, such as the brain. Cancer from other organs also may spread to the lungs. When cancer cells spread from one organ to another, they are called metastases.

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Lung cancers usually are grouped into two main types called small cell and non-small cell. These types of lung cancer grow differently and are treated differently. Non-small cell lung cancer is more common than small cell lung cancer. (cdc.gov.lungcancer)