Lung cancer can be caused by several factors, with smoking being the leading one. Other factors include secondhand smoke, exposure to radon gas, asbestos, air pollution, and a family history of lung cancer. To prevent lung cancer, avoid smoking, minimize exposure to secondhand smoke and pollutants, test your home for radon, and maintain a healthy diet rich in fruits and vegetables. Regular screenings, especially for high-risk individuals, are crucial for early detection.