Tobacco and Colorectal Cancer

Cigarettes cause colorectal cancer.^{Footnote 1Footnote 2Footnote 3}

• Key facts about tobacco use and colorectal cancer
• What is colorectal cancer?
• How does tobacco use increase the risk of colorectal cancer?
• How does quitting reduce the risk of colorectal cancer?
• Health benefits of quitting tobacco use at any age
• Call for free help to quit

Key facts about tobacco use and colorectal cancer

• Someone who smokes has up to 60% higher risk of colorectal cancer than someone who does not smoke.^{Footnote 4}
• Someone who quits smoking lowers their risk of colorectal cancer than those who continue to smoke.^{Footnote 2}
• The risk of colorectal cancer increases with the number of years spent smoking and the number of cigarettes smoked per day.^{Footnote 5Footnote 7}
• The longer someone smokes, the greater the risk for death from colorectal cancer.^{Footnote 1}
• In 2022, it was estimated there would be 24,300 new cases of colorectal cancer in Canada (excluding Quebec), and 9,400 colorectal cancer deaths, based on data from 1984-2019.^{Footnote 8}
• In Canada (excluding Quebec), 66% of people diagnosed with colorectal cancer are predicted to live beyond five years, according to 2015-2017 data.^{Footnote 9}

View health-related messages for all tobacco product packaging.

What is colorectal cancer?

The colon and rectum are part of the large intestine or large bowel. The colon absorbs water and nutrients from digested food and passes waste (stool or feces) to the rectum.

Cancers that occur in the colon or rectum are grouped together as colorectal cancer.^{Footnote 10}

Most colorectal cancers start as a growth on the inner lining of the colon or rectum. These growths are called polyps. Some polyps can become cancerous, and if not treated, can spread cancer to other parts of the body. ^{Footnote 9}

Symptoms of colorectal cancer often only appear when the cancer has advanced. They include constipation, diarrhea, bright red or very dark blood in the stool, fatigue, and unexplained weight loss.^{Footnote 11}

Treatments for colorectal cancer include surgery to remove part of the colon or rectum, radiation, or chemotherapy depending on the severity and location of the cancer.^{Footnote 12}

How does tobacco use increase the risk of colorectal cancer?

Some of the chemicals in tobacco smoke are carcinogenic, meaning they can cause genetic changes in cells of the colon and rectum, leading to the development of colorectal cancer.^{Footnote 1}

These chemicals or their metabolites are carried through the blood stream to the large bowel and stored in the colon and rectum prior to defecation. This can increase the development of polyps in the colon and rectum.^{Footnote 1}

How does quitting reduce the risk of colorectal cancer?

Quitting smoking reduces the risk of colorectal cancer.^{Footnote 2} The risk further decreases the earlier someone quits, and the longer they remain smoke-free.^{Footnote 6}

Quitting is one of the best ways to avoid the development of colorectal cancer and other tobacco-related diseases.^{Footnote 2}

If someone who smokes has colorectal cancer, quitting can still benefit them. Quitting smoking can improve recovery for cancer patients.^{Footnote 1}

Continuing to smoke after a cancer diagnosis can lower chances of survival and increase the risk for other cancers caused by tobacco smoke, such as lung cancer.^{Footnote 1}

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 2} Quitting at any age is beneficial to one's health.^{Footnote 2} Even people who have smoked or used tobacco heavily for many years benefit from it.^{Footnote 2Footnote 13} Quitting is the most important thing someone who smokes can do to improve their health.

Read more about the benefits of quitting smoking.

Call for free help to quit

Call the toll-free pan-Canadian quit line at 1-866-366-3667. Quit line counselling, alone or in combination with cessation medications, increases success in quitting.^{Footnote 2}