Smoking and Cancer

Key Points

Cigarette smoking causes 87 percent of lung cancer deaths and is responsible for most cancers of the larynx, oral cavity and pharynx, esophagus and bladder. Secondhand smoke is responsible for an estimated 3,000 lung cancer deaths among U.S. nonsmokers each year. Tobacco smoke contains thousands of chemical agents, including more than 60 substances that are known to cause cancer. The risk of developing smoking-related cancers, as well as noncancerous diseases, increases with total lifetime exposure to cigarette smoke. Smoking cessation has major and immediate health benefits, including decreasing the risk of lung and other cancers, heart attack, stroke and chronic lung disease.

Tobacco use, particularly cigarette smoking, is the single most preventable cause of death in the United States. Cigarette smoking alone is directly responsible for approximately 30 percent of all cancer deaths annually in the United States . Cigarette smoking also causes chronic lung disease (emphysema and chronic bronchitis), cardiovascular disease, stroke, and cataracts. Smoking during pregnancy can cause stillbirth, low birthweight, Sudden Infant Death Syndrome and other serious pregnancy complications. Quitting smoking greatly reduces a person's risk of developing the diseases mentioned, and can limit adverse health effects on the developing child.

What are the effects of cigarette smoking on cancer rates?

Cigarette smoking causes 87 percent of lung cancer deaths. Lung cancer is the leading cause of cancer death in both men and women. Smoking is also responsible for most cancers of the larynx, oral cavity and pharynx, esophagus and bladder. In addition, it is a cause of kidney, pancreatic, cervical and stomach cancers, as well as acute myeloid leukemia.

Are there any health risks for nonsmokers?

The health risks caused by cigarette smoking are not limited to smokers. Exposure to secondhand smoke, or environmental tobacco smoke (ETS), significantly increases the risk of lung cancer and heart disease in nonsmokers, as well as several respiratory illnesses in young children. (Secondhand smoke is a combination of the smoke that is released from the end of a burning cigarette and the smoke exhaled from the lungs of smokers.) Secondhand smoke has been classified as a known human carcinogen - a category reserved for agents for which there is sufficient scientific evidence that they cause cancer. The U.S. EPA has estimated that exposure to secondhand smoke causes about 3,000 lung cancer deaths among nonsmokers and is responsible for up to 300,000 cases of lower respiratory tract infections in children up to 18 months of age in the United States each year. For additional information on ETS, see the NCI fact sheet Environmental Tobacco Smoke.

What harmful chemicals are found in cigarette smoke?

Cigarette smoke contains about 4,000 chemical agents, including over 60 carcinogens. In addition, many of these substances, such as carbon monoxide, tar, arsenic, and lead, are poisonous and toxic to the human body. Nicotine is a drug that is naturally present in the tobacco plant and is primarily responsible for a person's addiction to tobacco products, including cigarettes. During smoking, nicotine is absorbed quickly into the bloodstream and travels to the brain in a matter of seconds. Nicotine causes addiction to cigarettes and other tobacco products that is similar to the addiction produced by using heroin and cocaine.

How does exposure to tobacco smoke affect the cigarette smoker?

Smoking harms nearly every major organ of the body. The risk of developing smoking-related diseases, such as lung and other cancers, heart disease, stroke and respiratory illnesses, increases with total lifetime exposure to cigarette smoke. This includes the number of cigarettes a person smokes each day, the intensity of smoking (i.e., the size and frequency of puffs), the age at which smoking began, the number of years a person has smoked and a smoker's secondhand smoke exposure.

How would quitting smoking affect the risk of developing cancer and other diseases?

Smoking cessation has major and immediate health benefits for men and women of all ages. Quitting smoking decreases the risk of lung and other cancers, heart attack, stroke, and chronic lung disease. The earlier a person quits, the greater the health benefit. For example, research has shown that people who quit before age 50 reduce their risk of dying in the next 15 years by half compared with those who continue to smoke. Smoking low-yield cigarettes, as compared to cigarettes with higher tar and nicotine, provides no clear benefit to health.

For additional information on quitting smoking, see the NCI fact sheet Questions and Answers About Smoking Cessation.

What additional resources are available?

For additional information about cancer or tobacco use, visit the NCI's website about tobacco. For help with quitting smoking, visit the NCI's smoking cessation website. Information about the health risks of smoking is also available from Centers for Disease Control and Prevention's Office.

Courtesy of the National Cancer Institute

  • Page last updated: Nov 10, 2012
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