Smoking is the primary cause of lung cancer, responsible for about 85% of all cases. It damages the cells lining the lungs, leading to genetic mutations that can develop into cancerous tumors.
Smoking and smokeless tobacco use significantly increase the risk of cancers of the mouth, throat, esophagus, and larynx. These products expose the delicate tissues of the oral cavity and throat to carcinogens, increasing the likelihood of abnormal cell growth.
Smoking has also been linked to cancers of the bladder, pancreas, kidney, cervix, and stomach, among others.
Exposure to secondhand smoke, also known as passive smoking, can be harmful as well. Non-smokers who are regularly exposed to smoke from others have an increased risk of lung cancer and other respiratory illnesses.