In Ontario, approximately 9,800, or 15%, of new cancer cases diagnosed in 2009 were attributed to smoking cigarettes. Because smoking rates have been historically much higher in males than females, more of these cases were in men (about 6,000) than in women (about 3,800).
Smoking cigarettes can cause many types of cancer, including cancers of the lung, oral cavity and pharynx, nasopharynx, nasal cavity and paranasal sinuses, esophagus, stomach, colon and rectum, liver, pancreas, larynx, cervix, ovary, kidney, bladder and other urinary, and bone marrow (myeloid leukemia).[1]In general, the risk of developing a smoking-related cancer is linked to the number of cigarettes smoked each day and the number of years someone smokes.
Smoking is most strongly tied to cancers of the respiratory and upper aerodigestive tracts, and is estimated to cause the largest proportion of lung (76% for men and 66% for women) and laryngeal cancers in Ontario (74% in men and 67% in women). It is also considered to be responsible for over one-third of cancers of the lip, oral cavity, pharynx and esophagus. Although a smaller proportion of colorectal cancers is caused by smoking (12.4% for men, 8.7% for women), this still represents a substantial number of cases because colorectal cancer is 1 of the most common cancers diagnosed in Ontario.
Tobacco smoking is a major preventable cause of death and disease, which is why tobacco control efforts aim to prevent people from starting to smoke and to support smokers in quitting and staying smoke-free. People who quit smoking have a lower risk of developing tobacco-related cancers than people who smoke, plus they get several other health benefits, including improvements in lung function and respiratory health, and reduced heart disease risk.[1][2]Quitting smoking can even help people who already have cancer by improving their healing and the effectiveness of their treatment, as well as reducing the risk of their cancer returning and developing new kinds of cancer.[3]
Over half of Ontario adult smokers have quit and the proportion of the population that still smokes cigarettes has gone down dramatically over the past several decades.[4]Despite these achievements, roughly one-fifth of adults age 20 years and older, or 2 million people, still smoke cigarettes daily or occasionally and the decline in smoking rates has slowed or stalled in recent years.[4]
Looking ahead, the total number of cancers caused by smoking in Ontario is expected to rise, even if smoking rates remain stable, due to ongoing population growth. Therefore, more strategies to promote quitting and to prevent people from starting to smoke are needed to reduce the burden of cancer related to tobacco smoking in Ontario.
Highlights
- Approximately 9,800 new cases of cancer diagnosed in Ontario in 2009 can be attributed to tobacco smoking.
- Smoking is estimated to cause the largest proportion of cancers of the lung and larynx. It also causes many other cancers in the respiratory and upper aerodigestive tract.
- Smoking is expected to continue to have a large impact on the burden of cancer in Ontario if smoking rates don’t go down.