The colon is what we commonly call the last 6 feet of the intestines, which leads from the small intestine to the rectum. The colon is sometimes referred to as the large intestine. The last part of the large intestine is the rectum.
Colon and rectal cancer, also called colorectal cancer, is the third most common cancer in Canada.
The risk of colorectal cancer increases as a person gets older. After 30, the risk at least doubles with each passing decade. Most doctors start screening at age 50. Men appear to be at greater risk for developing colon cancer.
Screening is crucial because colorectal cancer responds best to treatment if caught early. Treatment is most effective for people with localized colorectal cancer. People who may be at higher risk for colorectal cancer should speak with their doctor to decide on the best screening schedule for them.
The stage of a tumour is usually the best way of knowing its curability. Most cancers are staged or graded according to their size and, above all, the degree to which they have spread to other parts of the body. The stage depends heavily on whether lymph nodes are involved. Lymph nodes are bean-shaped concentrations of immune system cells that are found all over the body. They are interconnected by their own network of tubes, called the lymphatic system. Cancer often spreads through the lymphatic system to reach other organs – this jumping from one part of the body to another is called metastasis.
In colon cancer, stages 1 and 2 represent increasing degrees of penetration of the colon's wall. Stage 3 cancer has reached the nearby lymph nodes. Stage 4 has spread to other parts of the body (metastasized). Recurrent cancer has come back after an apparently successful treatment, often reappearing in the liver or lungs instead of the colon.