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Smoking and Lung Cancer
It has long been established that smoking causes lung cancer.1,2,3,4,5 Read more about lung cancer...
Facts
The risk of lung cancer increases sharply with the amount smoked,6 the number of years one has smoked,7 and the earlier one had started smoking.3Lung cancer risk also increases with the age of the smoker.7
The risk of dying from lung cancer is up to 25 times greater among smokers than people who never smoked, depending on how much they have smoked.2,8
Only 16% of people diagnosed with lung cancer are expected to be still alive 5 years after diagnosis.9 There were 18,560 deaths from lung cancer in Canada in 2007.10 Research has shown that in 2002, almost 80% of lung cancer deaths were due to smoking.11
Among people who have never smoked, long-term exposure to second-hand smoke also causes lung cancer.12 In Canada, 252 non-smokers died in 2002 from lung cancer due to exposure to second-hand smoke.11 The lung cancer risk from second-hand smoke exposure is 20% to 30% higher for those living with a smoker.12
These health warning messages address lung cancer for cigarettes and little cigars:
What is lung cancer?
Lung cancer is the leading cause of death from cancer among both males and females. It is the uncontrolled growth of abnormal cells in the lung, leading to the formation of a tumour.
Lung cancer symptoms include cough, chest pain, weight loss and sometimes the spitting up of blood or bloody mucus.
Treatment for lung cancer can involve surgery, chemotherapy, radiation or a combination of treatments.
How does smoking increase the risk of lung cancer?
Some of the chemicals in tobacco smoke cause, initiate or promote cancer. 13,14 These chemicals cause genetic changes in cells of the lung, which can lead to the development of lung cancer.1
In addition, some of these chemicals inhibit and damage the normal cleaning process by which the lungs get rid of foreign and harmful particles. Smoke destroys an important cleansing layer in the lungs, which in turn causes a build-up of mucus. The result is "smokers' cough," an alternative method for the lungs to try to clean themselves.15
The benefits of quitting
When people stop smoking, the risk of lung cancer starts to decrease. Ten years after quitting, the risk of lung cancer is about one-third to one-half of that of a smoker.15
People who quit, even at middle age, avoid much of the future risk associated with smoking. The earlier someone quits, the greater the long-term benefit.16,17
Quitting is more effective than other measures to avoid the development of lung cancer and other smoking-related diseases.
Need help to quit? Call the pan-Canadian quitline toll-free at 1-866-366-3667.
References
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. P.42-61.
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. P.21-63.
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. P.105-160.
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.
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.
6. Flanders WD, Lally CA, Zhu BP, Henley SJ and 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.
7. 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.
8. U.S. Department of Health and Human Services. Reducing the Health Consequences of Smoking: 25 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; 1989. P.43-55.
9. Canadian Cancer Society's Steering Committee: Canadian Cancer Statistics 2011. Toronto: Canadian Cancer Society, 2011.
10. Statistics Canada. Table 102-0552 - Deaths and mortality rate, by selected grouped causes and sex, Canada, provinces and territories, annual (2007), CANSIM (database). 2011 [updated 2010 Nov 15; cited 2011 Mar 15]. Available from: 
http://www5.statcan.gc.ca/cansim/a05?lang=eng&id=1020552.
11. Rehm J, Baliunas D, Brochu S, Fischer B, Gnam W, Patra J, et al. The costs of substance abuse in Canada 2002. Ottawa: Canadian Centre on Substance Abuse; 2006.
12. 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. P.423-435.
13. Rodgman, A., Perfetti, T.A. The chemical components of tobacco and tobacco smoke. (2009). CRC press, Florida, USA. ISBN 978-1-4200-7883-1.
14. Hecht SS. Research Opportunities Related to Establishing Standards for Tobacco Products Under the Family Smoking Prevention and Tobacco Control Act. Nicotine & Tobacco Research [http://ntr.oxfordjournals.org/] Commentary [accepted November 25, 2010]. Web Published 2011January;10.1093/ntr/ntq216. Available from: http://ntr.oxfordjournals.org/content/early/2011/01/09/ntr.ntq216.full.pdf
15. U.S. Department of Health and Human Services. The Health Benefits of 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; 1990. P.107-135.
16. 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.
17. International Agency for Research on Cancer. IARC Handbooks of Cancer Prevention, Tobacco Control, Vol. 11: Reversal of Risk After Quitting Smoking. Lyon (France); 2007. P.79-138.
