Colonic polyps are mucosal lesions that project into the lumen of the large bowel. Most colonic polyps cause no symptoms but they may cause rectal bleeding, mucus in stools, abdominal pain and rarely diarrhoea or constipation. If left untreated, there is a small risk (approximately 1 in 10) that polyps may develop into bowel cancer after several years.
Colonic polyps are usually removed by endoscopic snaring. Polyps that cannot be removed endoscopically are typically large, broad‑based, or situated in anatomically inaccessible areas (such as behind mucosal folds) where attempted endoscopic removal could result in bowel perforation. Polyps that are unsuitable for endoscopic removal need open or laparoscopic bowel resection.