Colon cancer. Coloured computed tomography (CT) scan of an axial section through the abdomen of a 69-year-old male patient, showing opacified loops (black, top) of the colon (large intestine) and the presence of a lesion (upper centre) suggestive of colon cancer. Most colorectal cancers are due to old age and lifestyle factors. Globally, colorectal cancer is the third most common form of cancer. Here, the colon has been inflated with air and a barium meal administered to the patient to aid in visualisation.