Colorectal cancer (CRC), also known as bowel cancer and colon cancer, is the development of cancer from the colon or rectum (parts of the large intestine).A cancer is the abnormal growth of cells that have the ability to invade or spread to other parts of the body.Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, and feeling tired all the time.

Most colorectal cancers are due to old age and lifestyle factors with only a small number of cases due to underlying genetic disorders.Some risk factors include diet, obesity, smoking, and lack of physical activity.