The majority of lung cancers start in the bronchi, which are the airways that lead to the lungs. There are different types of lung cancer. The most common is called non-small cell lung cancer, which includes adenocarcinoma, large cell carcinoma, and squamous cell carcinoma. The other type of lung cancer is small cell carcinoma (or oat cell carcinoma).
Each type grows at a different rate and responds differently to treatment. Cancer that has spread from other parts of the body to the lungs is also common.