Intended for healthcare professionals

Practice Uncertainties

Is surveillance colonoscopy necessary for all patients with bowel polyps?

BMJ 2020; 369 doi: (Published 15 May 2020) Cite this as: BMJ 2020;369:m1706
  1. Emma C Robbins, epidemiologist1,
  2. Kate Wooldrage, medical statistician1,
  3. Amanda J Cross, professor of cancer epidemiology1
  1. 1Cancer Screening and Prevention Research Group (CSPRG), Department of Surgery and Cancer, Imperial College London, London, UK
  1. Correspondence to: A J Cross amanda.cross{at}

What you need to know

  • Surveillance colonoscopy is advised in some patients who have had bowel polyps detected and removed to prevent future development of bowel cancer

  • There is a lack of data on long term bowel cancer risk after polypectomy and uncertainty remains regarding whether certain patients with polyps require surveillance (such as those with multiple diminutive (≤5 mm) adenomas)

  • Surveillance colonoscopy is burdensome on endoscopy services and carries a small risk (<0.5%) of serious complications, including bowel perforation and severe bleeding

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.

Box 1

High risk criteria for future bowel cancer after polypectomy (2019 UK surveillance guidelines3)

  • ≥2 adenomas or serrated polyps, at least one of which is “advanced” (adenoma ≥10 mm diameter or with high grade dysplasia, serrated polyp ≥10 mm or with dysplasia)

  • ≥5 adenomas or serrated polyps


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