Lung cancer is when a cancerous tumor forms in the lungs. The lungs are located behind the chest wall. When a person breathes in, the lungs take in oxygen. When a person breathes out, they release carbon dioxide.
There are two types of lung cancer: small cell lung cancer and non-small cell lung cancer. “Small cell” and “non-small cell” refer to how big the cancer cells are. There are different treatments for each type.