Colorectal cancer refers to malignant growths that occur in the colon and the rectum. The colon is sometimes referred to as the large bowel or large intestine and is that part of the digestive tract that absorbs water from the food that is eaten but can't digest. This results in waste that is eliminated from the body as stool or feces. The rectum is at the very end of the colon where waste is stored until it is passed as a bowel movement or stool. Together the colon and rectum make up the lower digestive tract.
Most colorectal cancers start out as small benign growths that are known as polyps.
There are a number of different types of polyps but those associated with colorectal cancers are known as adenomas. Adenomas grow very slowly. Not all adenomas turn into cancer but they do have the potential to do so. Because of this slow process of change, there is a long window of opportunity for doctors to find polyps and remove them before they become cancers. This is why colorectal cancer is the cancer that no one needs to have.