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Around 40,000 people are diagnosed with bowel cancer every year in England. As well as being the main test to detect cancer, colonoscopies can also prevent cancer. Unfortunately, colonoscopies are not perfect and sometimes a person develops bowel cancer after having a colonoscopy. This is referred to as a post-colonoscopy colorectal cancer (PCCRC).


We looked at all individuals who had undergone a colonoscopy in the English NHS between 2005 and 2013 who then went on to be diagnosed with bowel cancer within the three years following the colonoscopy. Cancers diagnosed 6-36 months after a colonoscopy were categorised as PCCRC.

To see if some individuals were more at risk of developing a PCCRC, we looked at the rates in relation to age, sex, socio-economic status and whether they had any pre-existing health conditions, including a history of inflammatory bowel disease or diverticular disease, whether they had ever previously had bowel cancer and whether they had previously undergone a colonoscopy.

The rate of PCCRC was then calculated for each colonoscopy provider in the English NHS.


The overall rate of PCCRC has fallen from 9% in 2005 to 6.5% in 2013. PCCRCs were more frequent in females, those with pre-existing health conditions, in people with inflammatory bowel disease and diverticular disease, in people who had undergone multiple colonoscopies and in people with a previous diagnosis of bowel cancer. PCCRCs were also more common in older patients.

The lowest rates of PCCRC were found in those performed as part of the Bowel Cancer Screening Programme. Colonoscopies performed at private providers for the NHS had much higher rates.

In the years 2011-2013 the rate of PCCRCs varied substantially across NHS Trusts with rates ranging from 3.3% in the best performing to 13.4% in the worst performing.

If all providers during the eight years of the study period had achieved the same rate of PCCRC as the colonoscopies performed as part of the Bowel Cancer Screening Programme, 3900 cases of colorectal cancer could have been diagnosed earlier or even prevented.


Although the rates of PCCRC are improving, significant difference between providers exists. There is a need for all providers of colonoscopy to examine their cases of PCCRC, and local reasons for them.

From this, providers may be able to identify measures which once put into practice will lead to improved rates and improved outcomes for patients.

The lower rates of PCCRC found in the Bowel Cancer Screening Programme colonoscopies is noteworthy. All colonoscopies performed as part of the Bowel Cancer Screening Programme take place within accredited screening centres by colonoscopists who have undergone an accreditation test and who adhere to strict performance criteria. This shows that where strict standards are applied, quality is better.

Project Outputs

Publication: Variation in post-colonoscopy colorectal cancer across colonoscopy providers in the English National Health Service Nicholas E Burr, Edmund Derbyshire, John Taylor, Simon Whalley, Venkataraman Subramanian, Paul J Finan, Matthew D Rutter, Roland Valori, Eva J A Morris, British Medical Journal, 2019.

BMJ Visual Summary:

BMJ Opinion:

Conference Presentation and award – British Society of Gastroenterology (BSG) 2018: “A Study of Post Colonoscopy Colorectal Cancer (PCCRC) in England

PCCRC Outlier Notification. NHS Trusts found to be an outlier in this research were notified and help was offered to identify cases for auditing. Twenty Two NHS Trusts were contacted and issued with the following notification. Seventeen Trusts were assisted in identifying their cases.

Results from this research were fed into the Getting It Right First Time programme. Getting It Right First Time is a national programme designed to improve medical care within the NHS by reducing unwarranted variations.

Follow on work

Individual Colonoscopy Provider Audits

Irritable Bowel Disease Audit

Bowel Cancer UK PCCRC National audit system. Bowel Cancer UK have awarded Professor Eva Morris and team funds to look at data from hospitals in England to identify post-colonoscopy colorectal cancers. The data will be linked and Trusts will be notified each time an undetected cancer is found. Trusts will then be asked to review cases which will help to identify the most common reasons why post-colonoscopy colorectal cancers occur.

Background work/relevant papers

Post-colonoscopy colorectal cancer (PCCRC) rates vary considerably depending on the method used to calculate them: a retrospective observational population-based study of PCCRC in the English National Health Service. Eva J Morris, Matthew D Rutter, Paul J Finan, James D Thomas, Roland Valori.