Colon cancer. Colonoscope (endoscope) view of polyps (villous adenoma) that have turned cancerous (adenocarcinoma) in a 64 year-old man. Villous adenomas are benign (non-cancerous) growths (polyps) of the mucosal lining of the lower gut. If they are diagnosed early they can be surgically removed, as they are prone to turning cancerous. Colon cancer, common in the developed world, is thought to be linked to a high-fat and low-fibre diet. Treatment involves removal of the polyps and anti-cancer drugs.