According to the Canadian Cancer Society, at least half of all cancers can be prevented through healthy living and policies that protect the health of Canadians.

One key is the elimination of cancer-causing substances at home, at work, and in our environment. Visit the Specific Environmental Contaminants page at the Canadian Cancer Society website for information about exposure to substances that cause cancer and how in some cases, there are safer alternatives. Cancer Care Ontario, through its Cancer 2020 report, also calls for increased research, surveillance and policy action to increase our understanding of and to reduce workplace and environmental exposures to carcinogens.

Tobacco use has long been identified as a key cause of lung cancer. According to Cancer Care Ontario, tobacco use is the single most important cause of cancer. Smoking causes about 90% of lung cancer deaths in women and almost 80% of lung cancer deaths in men. The risk of dying from lung cancer is more than 23 times greater among men who smoke cigarettes, and about 13 times greater among women who smoke cigarettes compared with those who have never smoked.

Healthy eating and active living are also key. According to Cancer Care Ontario, research has proven that more than one-third of cancers are attributable to poor diet, unhealthy body weight, and physical inactivity. These cancers can be prevented by eating a well-balanced diet rich in fruits and vegetables, being physically active, and maintaining a healthy body weight. Making lifestyle changes could lower the risk of cancer of the colon and rectum, mouth and throat, stomach, breast, prostate, uterus and kidney. These modifications may also reduce the risk of diabetes, heart disease, stroke and other chronic conditions.