Classified as small cell and non-small cell, lung cancer is the leading cause of cancer death. Learn how it develops and spreads.
Lung cancer is a cancer starts in the lungs. In order to understand lung cancer, it helps to know something about the structure of the lungs and how they work.
The lungs
The lungs are two sponge-like organs found in the chest. The right lung has 3 sections, called lobes. The left lung has 2 lobes. The left lung is smaller because the heart takes up more room on that side of the body.

