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Cigarette Smoking and Cancer: Questions and Answers 

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 (1). 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 

(SIDS), and other serious pregnancy complications (2). Quitting smoking greatly reduces a 

person’s risk of developing the diseases mentioned, and can limit adverse health effects on the 

developing child. 

1. What are the effects of cigarette smoking on cancer rates?

Cigarette smoking causes 87 percent of lung cancer deaths (1). Lung cancer is the 

leading cause of cancer death in both men and women (3). Smoking is also responsible 

for most cancers of the larynx, oral cavity and pharynx, esophagus, and bladder. In 

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 (see Question 1). 

• Secondhand smoke is responsible for an estimated 3,000 lung cancer 

deaths among U.S. nonsmokers each year (see Question 2). 

• Tobacco smoke contains thousands of chemical agents, including over 

60 substances that are known to cause cancer (see Question 3). 

• The risk of developing smoking-related cancers, as well as 

noncancerous diseases, increases with total lifetime exposure to 

cigarette smoke (see Question 4). 

• Smoking cessation has major and immediate health benefits, including 

decreasing the risk of lung and other cancers, heart attack, stroke, and 

chronic lung disease (see Question 5). 
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addition, it is a cause of kidney, pancreatic, cervical, and stomach cancers (2, 4), as well 

as acute myeloid leukemia (2). 

2. 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 (5). (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.) The U.S. Environmental Protection Agency (EPA), the National Institute of 

Environmental Health Science’s National Toxicology Program, and the World Health 

Organization’s International Agency for Research on Cancer (IARC) have all classified 

secondhand smoke as a known human carcinogen—a category reserved for agents for 

which there is sufficient scientific evidence that they cause cancer (5, 6, 7). 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 (5). For 

additional information on ETS, see the NCI fact sheet Environmental Tobacco Smoke, 

which can be found at http://www.cancer.gov/cancertopics/factsheet/Tobacco/ETS on the 

Internet. 

3. What harmful chemicals are found in cigarette smoke?

Cigarette smoke contains about 4,000 chemical agents, including over 60 carcinogens (8). 

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 (9). 

4. How does exposure to tobacco smoke affect the cigarette smoker?

Smoking harms nearly every major organ of the body (2). 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 (7). 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. 

5. How would quitting smoking affect the risk of developing cancer and other 

diseases? 
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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 (3). 

Smoking low-yield cigarettes, as compared to cigarettes with higher tar and nicotine, 

provides no clear benefit to health (2). For additional information on quitting smoking, 

see the NCI fact sheet Questions and Answers About Smoking Cessation, which can be 

found at http://www.cancer.gov/cancertopics/factsheet/Tobacco/cessation on the Internet. 

6. What additional resources are available?

For additional information about cancer or tobacco use, call 1–800–4–CANCER or visit 

the NCI’s Web site about tobacco at http://www.cancer.gov/cancerinfo/tobacco on the 

Internet. 

For help with quitting smoking, call NCI’s smoking cessation quitline at 

1–877–44U–QUIT or visit NCI’s smoking cessation Web site at 

http://www.smokefree.gov on the Internet. 

Information about the health risks of smoking is also available from Centers for Disease 

Control and Prevention’s Office on Smoking and Health (OSH) at 1–800–CDC–1311 

(1–800–232–1311) or via their Web site at http://www.cdc.gov/tobacco on the Internet. 

Selected References 

1. Ries LAG, Eisner MP, Kosary CL, et al. (eds). SEER Cancer Statistics Review, 

1975–2001, National Cancer Institute. Bethesda, MD, 2004 

(http://seer.cancer.gov/csr/1975_2001). 

2. U.S. Department of Health and Human Services. The Health Consequences of Smoking: 

A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and 

Human Services, Centers for Disease Control and Prevention, National Center for 

Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2004. 

 

3. American Cancer Society. Cancer Facts and Figures 2004. Atlanta, GA: American 

Cancer Society, 2004. 

4. U.S. Department of Health and Human Services. Targeting Tobacco Use: The Nation’s 

Leading Cause of Death. Atlanta, GA: U.S. Department of Health and Human Services, 

Centers for Disease Control and Prevention, 2003. 

5. U.S. Environmental Protection Agency. Respiratory Health Effects of Passive Smoking: 

Lung Cancer and Other Disorders. Washington, DC: U.S. Environmental Protection 

Agency, 1992. 
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6. U.S. Department of Health and Human Services. Report on Carcinogens: Tenth Edition. 

Research Triangle Park, NC: U.S. Department of Health and Human Services, Public 

Health Service, National Toxicology Program, 2002. 

7. International Agency for Research on Cancer. Tobacco Smoke and Involuntary Smoking. 

IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 83. Lyon, 

France, 2004. 

8. Centers for Disease Control and Prevention. Tobacco Use in the United States. 

Retrieved September 30, 2003, from: 

http://www.cdc.gov/tobacco/overview/tobus_us.htm. 

9. U.S. Department of Health and Human Services. Nicotine Addiction: A Report of the 

Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, 

Public Health Service, Centers for Disease Control, Center for Health Promotion and 

Education, Office on Smoking and Health, 1988. 

# # # 

Related Resources

Publications (available at http://www.cancer.gov/publications) 

• National Cancer Institute Fact Sheet 10.17, The Truth about “Light” Cigarettes: 

Questions and Answers

• National Cancer Institute Fact Sheet 10.18, Secondhand Smoke: Questions and 

Answers

• National Cancer Institute Fact Sheet 10.19, Questions and Answers About 

Smoking Cessation

National Cancer Institute (NCI) Resources

Cancer Information Service (toll-free)

 Telephone: 1–800–4–CANCER (1–800–422–6237) 

 TTY: 1–800–332–8615 

Online 

NCI’s Web site: http://www.cancer.gov 

LiveHelp, NCI’s live online assistance: 

https://cissecure.nci.nih.gov/livehelp/welcome.asp 

This fact sheet was reviewed on 11/4/04