Lung cancer: Role of smoking, other risk factors

Smoking is the main cause of lung cancer, responsible for around 85% of cases. Tobacco smoke contains harmful chemicals that damage lung cells and DNA, leading to cancer. The risk of lung cancer increases with the number of cigarettes smoked and the duration of smoking. Secondhand smoke exposure, occupational exposure to carcinogens, family history of lung cancer, and pre-existing lung diseases also contribute to the risk.