Colorectal cancer (CRC) is a type of cancer that begins in the colon or rectum. It is sometimes referred to as colon cancer or rectal cancer, depending on where it starts. The colon and rectum are part of the large intestine, which is the lower part of the body's digestive system. Most colorectal cancers start as a growth on the inner lining of the colon or rectum, known as a polyp. Over time, some polyps can turn into cancer.
