Colorectal cancer, less formally known as bowel cancer, is a cancer characterized by neoplasia in the colon, rectum, or vermiform appendix. Invasive cancers that are confined within the wall of the colon (TNM stages I and II) are often curable with surgery, For example, in England and Wales over 90% of patients diagnosed at this stage will survive the disease beyond 5 years. If left untreated, they spread to regional lymph nodes (stage III). In England and Wales, around 48% of patients diagnosed at this stage survive the disease beyond five years. Cancer that metastasizes to distant sites (stage IV) is usually not curable; approximately 7% of patients in England and Wales diagnosed at this stage survive beyond five years.