Colorectal cancer forms in the colon or rectum, the last part of the large intestine.
Colorectal cancer comes 3rd among the most common cancers in Canada, in both men and women. One in 14 men and 1 in 15 women are likely to have colorectal cancer in their life 1.
Colorectal cancer is much more common in industrialized countries. The habits of life, mainly food, also play a key role in its appearance. This explains, for example, the Japanese, little affected by colorectal cancer in Japan, are becoming just as much as their fellow Americans a few years after emigrating to the United States and adopted their diet.
Some people can contract because of an inherited predisposition. But in 75% of cases, heredity is not involved.
Colorectal cancer takes several years to form, like the majority of cancers. It usually does from polyps in the wall lining the inside of the colon. Polyps are small fleshy growths. There are several genres. Most often, they are mild. However, it is known that some of them can become cancerous. It takes an average of 10 years for a polyp to form a cancerous tumor. Polyp (non-cancerous or) sometimes cause digestive discomfort. For more information, see our fact sheet intestinal polyps.
Once the doctor finds polyps in a patient, it conducts analysis to determine if they pose a risk to her health.
At an advanced stage of evolution, colorectal cancer can spread to the lymph nodes, then to the liver and then in other parts of the body to form metastases.
In Canada, colorectal cancer is the second cause of cancer mortality. The death rate five years after diagnosis is approximately 40%, in two sexes.
Currently more than half of cases are diagnosed in people aged 70 years and over1. Health care professionals would like more people undergo regular screening tests from the age of 50, and earlier for those at risk. More cancer is detected early, it is possible to do so before the arrival of symptoms, the better the chances of recovery.
When to see
If blood in the stool or diarrhea or constipation persists, it is important to consult a doctor. For those at risk, it is advised