Is surveillance colonoscopy necessary for all patients with bowel polyps?

Bowel cancer affects about 42 000 people in the UK annually with around 16 000 deaths.1 It can be prevented by removing adenomatous and serrated polyps, the main precursors.2 Some patients remain at increased risk after polypectomy, and guidelines recommend such patients undergo surveillance by colonoscopy for prevention and early detection of bowel cancer.345

In the UK, post-polypectomy surveillance accounts for 20% of colonoscopies, placing great pressure on endoscopy resources.6 Colonoscopy carries a small risk (<0.5%) of serious complications, including bowel perforation and severe bleeding.78 It is therefore vital to minimise the number of surveillance colonoscopies performed unnecessarily in patients unlikely to develop bowel cancer after polypectomy, while ensuring that patients at increased risk receive surveillance.

Recently updated guidelines in the UK recommend a one-off surveillance colonoscopy at three years in patients deemed at high risk of bowel cancer post-polypectomy (box 1).3 These updated guidelines incorporate new data on the long term risk of bowel cancer after polypectomy. However, uncertainty remains around the natural history of serrated polyps and diminutive (≤5 mm) adenomatous polyps, and whether patients with such polyps require surveillance colonoscopy.