Smoking is the leading cause of cancer in the United States.

Smoking increases the risk of many types of cancer. These include:

• Lung cancer.
• Throat cancer.
• Mouth cancer.
• Nasal cavity cancer.
• Esophageal cancer.
• Stomach cancer.
• Pancreatic cancer.
• Kidney cancer.
• Bladder cancer.
• Cervical cancer.
• Acute myeloid leukemia.

A smoker’s risk of cancer can be 2 to 10 times higher than it is for a person who never smoked. This depends on how much and how long the person smoked.

Lung cancer is the leading cause of cancer death in both men and women. In 2014, about 19% of adult men and about 15% of adult women were smokers. In the last 30 years, the total number of smokers has decreased, especially among men. Since the 1980s, deaths caused by lung cancer in men have been decreasing.

From 2011 to 2014, smoking decreased among middle school and high school students. Cigarette smoking among male and female high school students of all ethnic groups increased markedly during the early 1990s, with rates between 20% and 30%. By 2021, smoking in this population had declined to 2%. Raising the legal age to buy and use tobacco products is being studied as a way to prevent or decrease smoking and other tobacco use among young people.

Smoking causes many other health problems.

Smoking is linked with many diseases besides cancer. These include:

• Heart disease.
• Stroke.
• Emphysema.
• Bronchitis.

Other health problems that may be linked to smoking are:

• Cataracts.
• Bone disease.
• Trouble becoming pregnant.

Smoking during pregnancy may cause problems such as slow growth of the fetus and low birth weight.

Being exposed to secondhand smoke increases the risk of cancer and other diseases.

Smoking can also affect the health of nonsmokers. Smoke that comes from the burning of a tobacco product or smoke that is exhaled by smokers is called secondhand smoke. Inhaling secondhand smoke is called involuntary or passive smoking.

The same cancer-causing chemicals inhaled by tobacco smokers are inhaled in lower amounts by people exposed to secondhand tobacco smoke. Nonsmokers who are exposed to secondhand smoke have a higher risk of lung cancer and coronary heart disease. Children exposed to tobacco smoke have higher risks of the following:

• Sudden infant death syndrome (SIDS).
• Worsened asthma.
• Ear infections.
• Respiratory problems such as lung infections, coughing, wheezing, or trouble breathing.

Quitting smoking improves health in smokers of all ages.

The risk of most health problems from smoking, including cancer and heart and lung disease, can be lowered by stopping smoking. People of all ages can improve their health if they quit smoking. Quitting at a younger age will improve a person's health even more. People who quit smoking cut their risk of lung cancer by 30% to 50% after 10 years compared to people who keep smoking, and they cut their risk of cancer of the mouth or esophagus in half within 5 years after quitting.

The damage caused by smoking is even worse for people who have had cancer. They have an increased risk of cancer recurrence, new cancers, and long-term side effects from cancer treatment. Quitting smoking and stopping other unhealthy behaviors can improve long-term health and quality of life.

The Public Health Service has a set of guidelines called Treating Tobacco Use and Dependence. It asks health care professionals to talk to their patients about the health problems caused by smoking and the importance of quitting smoking.

Different ways to quit smoking have been studied. The following are the most common methods used to help smokers quit:

There are new and different types of tobacco and nicotine products.

The use of new or different types of tobacco products and devices that deliver nicotine is increasing rapidly in the United States, especially the use of electronic-cigarettes (e-cigarettes) by adults and adolescents.

Examples of new and different tobacco and nicotine products and devices include the following:

• E-cigarettes.
• Small cigars.
• Water pipes (hookahs) for smoking tobacco.
• Flavored smokeless tobacco products.

More studies are needed to understand the risks and benefits of using these products.

Cancer prevention clinical trials are used to study ways to prevent cancer.

Cancer prevention clinical trials are used to study ways to lower the risk of developing certain types of cancer. Some cancer prevention trials are conducted with healthy people who have not had cancer but who have an increased risk for cancer. Other prevention trials are conducted with people who have had cancer and are trying to prevent another cancer of the same type or to lower their chance of developing a new type of cancer. Other trials are done with healthy volunteers who are not known to have any risk factors for cancer.

The purpose of some cancer prevention clinical trials is to find out whether actions people take can prevent cancer. These may include eating fruits and vegetables, exercising, quitting smoking, or taking certain medicines, vitamins, minerals, or food supplements.

New ways to help smokers quit are being studied in clinical trials.

Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.

About PDQ

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

Purpose of This Summary

This PDQ cancer information summary has current information about the prevention and cessation of cigarette smoking and the control of tobacco use. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Reviewers and Updates

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Updated") is the date of the most recent change.

The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Screening and Prevention Editorial Board.

Clinical Trial Information

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).

Permission to Use This Summary

PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary].”

The best way to cite this PDQ summary is:

PDQ® Screening and Prevention Editorial Board. PDQ Cigarette Smoking. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/about-cancer/causes-prevention/risk/tobacco/quit-smoking-pdq. Accessed <MM/DD/YYYY>. [PMID: 26389305]

Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 3,000 scientific images.

Disclaimer

The information in these summaries should not be used to make decisions about insurance reimbursement. More information on insurance coverage is available on Cancer.gov on the Managing Cancer Care page.

Contact Us

More information about contacting us or receiving help with the Cancer.gov website can be found on our Contact Us for Help page. Questions can also be submitted to Cancer.gov through the website’s E-mail Us.