Prevention and Cessation of Cigarette Smoking: Control of Tobacco Use (PDQ®)
Cancer Information Summaries « English « Health professionals « P
Summary of Evidence
Note: A separate PDQ summary on Levels of Evidence for Cancer Screening and Prevention Studies is also available.
The cancer prevention summaries in PDQ refer to cancer prevention, defined as a reduction in the incidence of cancer. The PDQ includes summaries generally classified by histological type of cancer, especially when there are known risk factors for the specific types of cancer. This summary addresses a specific risk factor, tobacco use, which is associated with a large number of different cancers (and other chronic diseases) and unequivocally contains human carcinogens. [1] The focus of this summary is on clinical interventions by health professionals that decrease the use of tobacco.
Effects of Smoking Cessation
Based on solid evidence, cigarette smoking causes various cancers, including but not limited to lung cancer. Smoking avoidance and smoking cessation result in decreased incidence and mortality from cancer.
Description of the Evidence
- Study Design: Evidence obtained from a randomized controlled trial.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: The relative risk (RR) of several cancers is much greater in cigarette smokers compared with nonsmokers (depending on the anatomical site of the cancer and the intensity and duration of smoking, the RR can range from twofold to tenfold or greater in smoking populations). A reduction of 15% is seen in the RR of all-cause mortality in heavy smokers subjected to intensive clinical cessation interventions.
- External Validity: Good.
Counseling and Smoking Cessation
Based on solid evidence, counseling by a health professional improves smoking cessation rates (as does simple advice from a physician to stop smoking).
Description of the Evidence
- Study Design: Evidence obtained from randomized controlled trials.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: Counseling improves cessation rates (physician advice: odds ratio [OR], 1.74; 95% confidence interval [CI], 1.48 – 2.05). [2]
- External Validity: Good.
Drug Treatment and Smoking Cessation
Based on solid evidence, drug treatments, including nicotine replacement therapies (gum, patch, spray, lozenge, and inhaler), antidepressant therapy (e.g., bupropion), and nicotinic receptor agonist therapy (varenicline), result in better smoking cessation rates than placebo.
Description of the Evidence
- Study Design: Evidence obtained from randomized controlled trials.
- Internal Validity: Good.
- Consistency: Good.
- Magnitude of Effects on Health Outcomes: Treatments, alone or in combination, improve cessation rates over placebo after 6 months (OR, 1.77; 95% CI, 1.66 – 1.88). [3]
- External Validity: Good.
References
This record was last updated on February 26th, 2009.
About the PDQ Cancer Information Summaries from the National Cancer Institute
PDQ (Physician Data Query) is a comprehensive cancer database published by the National Cancer Institute (NCI), which is part of the National Institutes of Health (NIH). It contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, and supportive care, and complementary and alternative medicine; a registry of cancer clinical trials; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care.
The PDQ Cancer Information Summaries are peer reviewed and updated monthly by six editorial boards comprised of specialists in adult treatment, pediatric treatment, supportive care, screening and prevention, genetics, and complementary and alternative medicine. The Boards review current literature from more than 70 biomedical journals, evaluate its relevance, and synthesize it into clear summaries. Many of the summaries are also available in Spanish.
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