Colon and Rectal Cancer (also known as colorectal cancer) is a major cancer affecting millions worldwide. It’s one of the most common types of cancer and is responsible for many cancer-related deaths. The colon and rectum are two important parts of your digestive system. The colon (sometimes called the large intestine) is responsible for absorbing water and electrolyte levels from the remaining food that can’t be digested and producing stool before it passes through your rectum and out of your body.