Smoking is the most important risk factor for lung cancer. The Center for Disease Control and Prevention (CDC) estimates that smoking causes almost nine out of ten lung cancers. Cigarette smoke contains thousands of chemicals. Some damage the lungs directly and can cause permanent lung damage. Many of the chemicals in smoke also damage the DNA in the cells of the lungs. Over time, damage to the DNA causes mutations, which can lead to lung cancer.
This information is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment, and should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.