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Smoking Causes Cancer

Smoking causes an estimated 1 in 5 of all cancer deaths.¹ Smoking is a cause of cancers of the lung, larynx (voice box), pharynx (throat), oral cavities, oesophagus, bladder, kidney, pancreas, stomach, cervix and the blood. ²^,³

Cancer is the leading cause of death⁴ and burden of disease in Australia.⁵ Tobacco use is responsible for around 20% of Australia’s deaths and disease burden from cancer.¹^,⁵ In 2003, more than 7,700 cancer deaths and 10,300 new cases of cancer in Australia were estimated to be caused by smoking. Of these, an estimated 180 deaths and more than 330 new cases were in persons under the age of 50 years.¹ These figures show that smoking can cause cancer in young people.

Tobacco smoke is identified as a human carcinogen (cancer-causing substance).³ Tobacco smoke is a mixture of over 4000 chemicals and more than 60 of these chemicals have been identified as cancer-causing in animals.⁶

The toxins in tobacco smoke go everywhere in the body that the blood flows.² The cancer-causing substances in tobacco smoke can interrupt normal cell growth, causing cells to multiply too fast or develop abnormally, which may result in the formation of cancer.⁷

Smoking tobacco in any form including cigarettes, bidis, pipes and cigars can cause cancer in many parts of the body.⁸ Inhaling the substances created by burning tobacco, in any form, is harmful to the human body.

Scientific evidence has established that smoking is a cause of cancers of the lung, larynx (voice box), pharynx (throat), oral cavities, oesophagus, bladder, kidney, pancreas, stomach, cervix and the blood.² Evidence indicates smoking may also cause colorectal² and liver cancer.²^,³ Some studies have also found a link between smoking and other cancers including cancer of the vulva⁹ and penis.¹⁰ As new research is conducted, smoking may be identified as causing or contributing to other types of cancer.

The risk of developing cancer from smoking generally increases the longer a person smokes and the more cigarettes they smoke. Importantly, the risk of developing most cancers generally decreases after quitting smoking completely. ⁷

While quitting at any age has benefits, the earlier you quit the lower your risk of developing smoking related cancers.¹¹

Cancers of the head and neck

Smoking is a major cause of cancers of the mouth, including the tongue and lips, and cancers of the nose, throat (pharynx) and voice box (larynx).² In Australia, each year around 2,400 people are diagnosed with cancers of the head and neck and they cause around 900 deaths.¹² You can reduce your risk by quitting. Five years after quitting smoking your risk of developing mouth and throat cancer is halved.² Also see the fact sheets ‘Smoking causes mouth and throat cancer’ and ‘Cigar smoking causes mouth and throat cancer’ for more information.

Oesophageal Cancer

Smoking significantly increases your risk of getting cancer of the oesophagus.²^,³ Smoking is estimated to cause around a half of all cases of oesophageal cancer in Australia.¹An estimated 572 deaths from oesophageal cancer in Australia were caused by smoking in 2003.⁵ Your risk of developing oesophageal cancer increases the more cigarettes you smoke per day and the longer you smoke. You can reduce your risk by quitting. Five years after quitting the risk of developing oesophageal cancer is halved.²

Lung Cancer

Lung cancer is the leading cause of cancer deaths in Australia¹ and most cases are caused by smoking. In 2003, an estimated 6,300 people died in Australia from lung cancer caused by smoking.⁵ Lung cancer doesn’t just happen to older people. In 2003, 26 new cases and 12 deaths from lung cancer were in persons under the age of 35 years.¹² You can reduce your risk by quitting. Your risk of developing lung cancer drops by up to 50% ten years after quitting smoking.¹³ Also see the fact sheet ‘Smoking causes lung cancer’ for more information.

Stomach Cancer

Smoking is a cause of stomach cancer.²^,³ A smoker’s risk of getting stomach cancer is on average 50-60% higher than a non-smoker’s.⁸ Your risk of developing stomach cancer increases the longer you smoke and the more you smoke and decreases with increasing time after quitting.²^,³

Pancreas Cancer

Smoking increases the risk of developing cancer of the pancreas.²^,³ In 2003, pancreatic cancer was the fifth most common cause of cancer death in Australia for both males and females causing 1,882 deaths.¹ A smoker’s risk of developing pancreatic cancer is about double that of someone who has never smoked.¹⁴ Your risk of developing pancreatic cancer increases the longer you smoke and the more you smoke and decreases with increasing time after quitting.²^,³

Liver Cancer

Smoking is a cause of cancer of the liver.³ Many of the toxins in tobacco smoke are processed by the liver, exposing the liver to cancer-causing substances.² Even in studies controlling for other known causes of liver cancer (such as alcohol use and hepatitis B and C infections) a smoker’s risk of developing liver cancer remains higher than a non-smoker’s.⁸ Smoking may also increase the risk of chronic hepatitis B and C infection progressing to liver cancer.⁸ Your risk of developing liver cancer increases the more you smoke and generally decreases with increasing time after quitting.¹⁴

Bladder and other renal cancer

Tobacco smoking is a cause of cancer of the bladder, ureter , kidney and renal pelvis.²^,³^,¹⁴ For those smoking more than a pack a day, the risk of dying from bladder cancer is three to five times that of a non-smoker.¹⁵ Many of the toxins from tobacco smoke are cleared from the body through the kidneys, exposing the kidney, renal pelvis, ureter and bladder to cancer-causing substances.² Your risk of developing bladder and renal cancer increases the longer you smoke and the more cigarettes you smoke anddecreases after quitting.²^,³^,¹⁴

Colorectal cancer

Colorectal cancer is the second most common cause of cancer deaths in Australia, causing 4,372 deaths in 2003.¹ A number of studies have found an increased risk of colorectal cancer among smokers.² ^,3Your risk increases the longer you smoke and the earlier you started and decreases with increasing time after quitting.²^,³

Cancer of the Female Reproductive System

Smoking is a cause of cancer of the cervix.²^,³ Tobacco specific carcinogens (cancer-causing substances) have been found in the cervical mucus of smokers.¹⁵ Smokers and former smokers risk of developing cancer of the cervix is about double that of never smokers.⁸ The risk remains after taking into account other risk factors for cervical cancer including infection with the human papilloma virus (HPV), a likely factor in most cases.²^,⁸ Your risk of developing cervical cancer increases the longer you smoke and the more cigarettes you smoke.²

Smoking is also associated with an increased risk of cancer of the vulva.⁹ While vulval cancer is rare, an estimated 40% of cases in Australia are thought to be caused by smoking.¹ Also see the fact sheet ‘Smoking and the female reproductive system’ for more information on the effects of smoking on female reproduction.

Cancer of the blood

Smoking is a known cause of acute myeloid leukemia.²^,³ Leukemia is a cancer of cells that make the blood in bone marrow - the soft part in the middle of your bones.¹⁶ Cigarette smoke contains substances, such as benzene, which are known causes of human leukemia.² The risk of developing acute myeloid leukemia increases the longer you smoke and the more you smoke. For those smoking more than a pack a day, the risk is double that of a non smoker.² Further research is required on the impact of quitting as a number of studies indicate that the risk remains elevated after quitting smoking.²

Exposure to secondhand smoke

Exposure to secondhand smoke increases your risk of cancer. Scientific evidence concludes that second-hand smoke causes lung cancer in non smokers and suggests that it may also cause breast cancer and nasal sinus cancers in non-smoking adults.¹⁷ Non-smokers who are exposed to second-hand smoke at home or work have a 20-30% increased risk of developing lung cancer.¹⁸

Emerging evidence also suggests that pre and post-natal exposure to second-hand smoke may cause some childhood cancers including leukemia’s, lymphomas, and brain tumors.¹⁷ Other studies suggest that children of fathers who smoke have an increased risk of developing childhood cancers, possibly as a result of damage to the father’s sperm.¹⁷ Also see the fact sheet ‘Smoking harms unborn babies’ for more information.

1. AIHW (Australian Institute of Health and Welfare) & AACR (Australasian Association of Cancer
Registries) 2007. Cancer in Australia: an overview, 2006. Cancer Series no. 37. Cat. No. CAN 32.
Canberra: AIHW.
2. U.S. Department of Health and Human Services. 2004 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.
3. IARC. 2002. IARC Monographs on the evaluation of carcinogenic risks to humans: Volume 83; Tobacco smoke and involuntary smoking; Summary of data reported and evaluation (PDF). International Agency for Research on Cancer. Lyon, France.
4. Australian Bureau of Statistics. 2007. Causes of Death, Australia, 2005 (PDF). Cat. no. 3303.0 Canberra.
5. Begg S, Vos T, Barker B, Stevenson C, Stanley L, Lopez AD. 2007. The burden of disease and injury in Australia 2003. PHE 82. Canberra: AIHW.
6. Hoffman D, Hoffman I and El-Bayoumy K. The Less Harmful Cigarette: A Controversial Issue; A Tribute to Ernst L. Wynder. Chemical Research in Toxicology. July 2001, 14(7): 767-790.
7. U.S. Department of Health and Human Services. 2004 Surgeon General’s Report: Smoking Among Adults in the United States: Cancer Highlights. Centers for Disease Control and Prevention. (printed 10 July 2007)
8. Vineis P, Alavanja M, Buffler P, Fontham E, Franceschi S, Gao YT, Gupta PC, Hackshaw A, Matos E, Samet J, Sitas F, Smith J, Stayner L, Straif K, Thun MJ, Wichmann HE, Wu AH, Zaridze D, Peto R, Doll R. Tobacco and Cancer: Recent Epidemiological Evidence. Journal of the National Cancer Institute. 2004, 96(2): 99-106.
9. U.S. Department of Health and Human Services. 2001. Women and Smoking: A Report of the Surgeon General U.S. Department of Health and Human Services. Public Health Service. Office of the Surgeon General.
10. Daling JR, Madeleine MM, Johnson LG, Schwartz SM, Shera KA, Wurscher MA, Carter JJ, Porter PL, Gllowary DA, McDougall JK, Krieger JN. Penile cancer: Importance of circumcision ,human papillomavirus and smoking in in situ and invasive disease. International Journal of Cancer. 11 April 2005. 116 (4) 606-616. [abstract]
11. Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking: 50 years observation on male British doctors. British Medical Journal. June 2004, 328:1519.
12. Australian Institute of Health and Welfare (AIHW) 2007. ACIM (Australian Cancer Incidence and Mortality) Books. AIHW: Canberra. (printed 25 July 2007)
13. U.S. Department of Health and Human Services. 2004. The health consequences of smoking: a report of the Surgeon General, What it means to you (PDF). 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.
14. IARC. 2004. IARC Monographs on the evaluation of carcinogenic risks to humans: Volume 83; Tobacco smoke and involuntary smoking. International Agency for Research on Cancer, Lyon, France.
15. American Council on Science and Health. 2003. Cigarettes: What the warning label doesn’t tell you. Second Edition, New York, American Council on Science and Health.
16. The Cancer Council Victoria. 2005. Leukaemia: A guide for people with cancer, their families and friends (PDF). (printed July 2007)
17. U.S. Department of Health and Human Services. 2006. 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, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health.
18. U.S. Department of Health and Human Services. 2006. The health consequences of involuntary exposure to tobacco smoke: a report of the Surgeon General, Secondhand smoke: what it means for you. [Atlanta, Ga.]: U.S. Dept. of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Centre for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health. Washington.