Tobacco and lung cancer

Smoking is the main cause of lung cancer, which is the leading cause of cancer death.Footnote 1Footnote 2Footnote 3Footnote 4Footnote 5Footnote 6Footnote 7

Key facts about tobacco use and lung cancer

  • People who smoke are 25 times more likely to die from lung cancer compared to someone who has never smoked.Footnote 6
  • This risk increases sharply with the number of cigarettes smoked, the number of years spent smoking, and the age of the person smoking.Footnote 6Footnote 8Footnote 9
  • In 2022, it was estimated there would be 30,000 new cases of lung cancer and 20,700 deaths from lung cancer in Canada (excluding Quebec), accounting for 24.3% of deaths due to cancer.Footnote 10
  • In Canada (excluding Quebec), only 22% of people diagnosed with lung cancer are predicted to live beyond five years, according to 2015-2017 data.Footnote 7

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What is lung cancer?

Lung cancer is the uncontrolled growth of cells in the lung or airways, leading to the formation of a tumour. Lung cancer symptoms include coughing, chest pain, unexplained weight loss, and spitting up blood or bloody mucus.

Treatment for lung cancer can involve a combination of chemotherapy, radiation, and surgery to remove part of or the entire affected lung.Footnote 11

How does tobacco use increase the risk of lung cancer?

A number of chemicals in tobacco smoke are carcinogenic, meaning they have the potential to cause cancer in the cells of the lungs or airways and other parts of the body.Footnote 1Footnote 12

Some of these chemicals damage the normal cleaning process of the lungs to remove foreign and harmful particles.Footnote 13 The result is a buildup of mucus and the development of what is commonly known as "smoker's cough", an alternative way for the lungs to rid the airways of unwanted substances.Footnote 13

The damage to lung function due to smoking increases the risk of several respiratory diseases. Having a history of lung disease and poorer lung function increases one's risk for cancer.Footnote 14Footnote 15

Approximately 1 in 15 Canadians will be diagnosed with lung cancer, mainly caused by smoking.Footnote 7 An estimated 72% of lung cancer cases in Canada are caused by smoking.Footnote 16

Exposure to second-hand smoke in the home can also increase the risk of lung cancer by 20-30% in people who have never smoked.Footnote 17

How does quitting reduce the risk of lung cancer?

When someone stops smoking, their risk of lung cancer starts to decrease.Footnote 18 Ten to fifteen years after quitting, their risk of lung cancer is about half that of someone who continues to smoke.Footnote 12

The earlier someone quits, the greater the long-term benefit.Footnote 19Footnote 20

Quitting is one of the best ways to avoid the development of lung cancer and other smoking-related diseases.Footnote 12

For patients with early stage lung cancer, quitting can slow the progression of lung cancer and significantly reduces the risk of death.Footnote 21

Continuing to smoke after a cancer diagnosis can also increase the risk for other cancers caused by smoking.Footnote 6

Health benefits of quitting tobacco use at any age

Quitting tobacco use reduces the risk of premature death, improves health, and enhances quality of life.Footnote 12 Quitting at any age is beneficial to one's health.Footnote 12 Even people who have smoked or used tobacco heavily for many years benefit from it.Footnote 1Footnote 12 Quitting is the most important thing someone who smokes can do to improve their health.

For help to quit

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Footnotes

Footnote 1

U.S. Department of Health and Human Services. The Health Consequences of Smoking. A Report of the Surgeon General. Atlanta, GA: 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.

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Footnote 2

U.S. Department of Health and Human Services. The Health Consequences of Smoking: Cancer. A Report of the Surgeon General. Atlanta, GA: 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; 1982.

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Footnote 3

National Cancer Institute. Tobacco Control Monograph No. 9: Cigars: Health Effects and Trends. Bethesda (MD): US Department of Health and Human Services, National Institutes of Health, National Cancer Institute; 1997.

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Footnote 4

Doll R, Hill AB. The mortality of doctors in relation to their smoking habits: a preliminary report. British Medical Journal. 1954;1(4877):1451-5. doi: 10.1136/bmj.328.7455.1529.

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Footnote 5

Doll R, Hill AB. Lung cancer and other causes of death in relation to smoking: a second report on the mortality of British doctors. British Medical Journal. 1956;2(5001):1071-81. doi: https://doi.org/10.1136/bmj.2.5001.1071.

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Footnote 6

U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta, GA: 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; 2014.

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Footnote 7

Canadian Cancer Statistics Advisory Committee. Canadian Cancer statistics 2021. Toronto, ON: Canadian Cancer Society: 2021. http://cancer.ca/Canadian-Cancer-Statistics-2021-EN

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Footnote 8

Flanders WD, Lally CA, Zhu BP, Henley SJ, Thun, MJ. Lung cancer mortality in relations to age, duration of smoking, and daily cigarette consumption: results from Cancer Prevention Study II. Cancer Research. 2003;63(19):6556-62. PMID: 14559851.

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Footnote 9

Knoke JD, Shanks TG, Vaughn JW, Thun MJ, Burns DM. Lung cancer mortality is related to age in addition to duration and intensity of cigarette smoking: an analysis of CPS-I data. Cancer Epidemiology, Biomarkers & Prevention. 2004;13(6):949-57. https://doi.org/10.1158/1055-9965.949.13.6

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Footnote 10

Brenner DR, Poirier A, Woods RR, Ellison LF, Billette JM, Demers AA, Zhang SX, Yao C, Finley C, Fitzgerald N, Saint-Jacques N. Projected estimates of cancer in Canada in 2022. CMAJ. 2022 May 2;194(17):E601-7.

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Footnote 11

Centers for Disease Control and Prevention. How is Lung Cancer Diagnosed and Treated? Updated 2021. Accessed June 28, 2022

https://www.cdc.gov/cancer/lung/basic_info/diagnosis_treatment.htm#:~:text=People%20with%20non-small%20cell%20lung%20cancer%20can%20be,usually%20treated%20with%20radiation%20therapy%20and%20chemotherapy.%20Surgery.

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Footnote 12

U.S. Department of Health and Human Services. Smoking Cessation: A Report of the Surgeon General. Atlanta, GA: 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; 2020.

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Footnote 13

U.S. Department of Health and Human Services. How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease: A Report of the Surgeon General. Atlanta, GA: 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; 2010.

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Footnote 14

Brenner DR, McLaughlin JR, Hung RJ. Previous lung diseases and lung cancer risk: A systematic review and meta-analysis. PLoS ONE. 2011;6(3): e17479. https://doi.org/10.1371/journal.pone.0017479

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Footnote 15

Mannino DM, Aguayo SM, Petty TL, Redd SC. Low lung function and incident lung cancer in the United States: Data from the First National Health and Nutrition Examination Survey Follow-up. Arch Intern Med. 2003;163(12):1475–1480. doi:10.1001/archinte.163.12.1475.

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Footnote 16

Poirier AE, Ruan Y, Grevers X, Walter SD, Villeneuve PJ, Friedenreich CM, et al. Estimates of the current and future burden of cancer attributable to active and passive tobacco smoking in Canada. Prev Med. 2019;122:9–19.

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Footnote 17

U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke. A Report of the Surgeon General. Atlanta, GA: 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; 2006.

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Footnote 18

Tindle HA, Stevenson Duncan M, Greevy RA, et al. Lifetime smoking history and risk of lung cancer: Results from the Framingham Heart Study. J Natl Cancer Inst. 2018;110 (11):1201-1207. https://doi.org/10.1093/jnci/djy041

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Footnote 19

Peto R, Darby S, Deo H, Silcocks P, Whitley E, Doll R. Smoking, smoking cessation, and lung cancer in the UK since 1950: Combination of national statistics with two case-control studies. BMJ. 2000;321(7257):323-9. https://doi.org/10.1136/bmj.321.7257.323

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Footnote 20

International Agency for Research on Cancer. IARC Handbooks of Cancer Prevention, Tobacco Control, Vol. 11: Reversal of Risk After Quitting Smoking. Lyon (France); 2007.

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Footnote 21

Parsons A, Daley A, Begh R, Aveyard P. Influence of smoking cessation after diagnosis of early stage lung cancer on prognosis: Systematic review of observational studies with meta-analysis. BMJ. 2010;340: b5569. doi: 10.1136/bmj.b5569.

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