
Lung cancer: 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. Lung cancers usually are grouped into two main types called small cell and non-small cell (including adenocarcinoma and squamous cell carcinoma). These types of lung cancer grow differently and are treated differently. Non-small cell lung cancer is more common than small cell lung cancer Causes: 1. Smoking: Cigarette smoking is the leading cause of lung cancer. It is responsible for the majority of cases, and the risk increases with the duration and intensity of smoking. 2 . Secondhand smoke : Being exposed to tobacco smoke from others can also increase the risk of developing lung cancer. 3. Radon gas: Exposure to high levels of radon, a naturally occurring radioactive gas that can seep into buildings, can increase the ...