Reducing the rates of undetected bowel cancers in England

Lead Researcher: Professor Eva Morris

Location: University of Oxford

Grant award: £149,422

Colonoscopy is the main test used to diagnose bowel cancer, but it isn’t always able to identify every case of the disease. Professor Eva Morris investigated why some bowel cancers go undetected during a colonoscopy and explored ways to help reduce the number of undetected cancers in the future.

The challenge

A colonoscopy is a thin tube with a camera on the end, used to look inside the bowel. It's the main test used to diagnose bowel cancer. It can also help to prevent bowel cancer developing in the first place, by removing pre-cancerous growths (known as polyps) that can develop into bowel cancer.

However, no test is 100% reliable and sometimes a cancer (or pre-cancerous growth) is not found during a colonoscopy. This type of cancer is known as a post-colonoscopy colorectal cancer or an undetected cancer.

Bowel cancer is treatable and curable especially if diagnosed early and nearly everyone survives bowel cancer if diagnosed at the earliest stage. Undetected cancers (or pre-cancerous growths) at colonoscopy, can mean that cancers are diagnosed later. Recent research has shown there are a high number of undetected cancers in England and big differences between hospitals.

The science behind the project

Professor Morris and her team looked at data from hospitals in England to identify cases where bowel cancers went undetected during a colonoscopy. The researchers linked this data, so that each time a new undetected cancer was found, the hospital was made aware of it.

They asked hospitals to review any undetected cancer cases in detail, to help to understand what happened and why the cancer was not found.

The research team looked at all the cases of undetected cancers across all the hospitals to identify the most common reasons for bowel cancers not being found.

Results

The team analysed the data gathered from 1,724 post-colonoscopy bowel cancer cases and reviewed in 126 hospitals.

Although some of the cases were due to new growths that had developed since the colonoscopy, the results show that nearly 7 in 10 of these cases could have been avoided and were caused by:

• A growth being missed during the colonoscopy, when the procedure seemed to be good enough
• A growth being missed during the colonoscopy, when the clinical team knew the procedure hadn’t been good enough — for example, due to insufficient bowel prep
• A growth being spotted during the colonoscopy but not being removed
• A growth being spotted and removed during the colonoscopy but the removal not being done properly

Other cases were caused by problems separate to the colonoscopy, such as appointments not being made.

Other outcomes

The findings have been shared at national and international conferences, as well as many NHS events and have been received enthusiastically across the endoscopy field. Many NHS endoscopy teams have asked for access to the full results to help improve their services. Professor Morris' team have also developed an auditing tool to keep collecting new data, to help clinicians identify any issues in their services.

The team is working with the NHS on how the tool can become an integrated part of NHS practice, so that the data collection and learnings can be ongoing. Health services in other countries including the USA, Canada and the Netherlands are interested in adopting this approach.

The project has also helped support a successful grant application to the National Institute for Health Research for £249,548 to adapt the tool for oesophageal and gastric cancers missed during endoscopy.

What difference will this project make?

This audit tool allows endoscopy services to monitor cases where cancers are missed during colonoscopy and understand why this happens. The knowledge can then be used to improve procedures and reduce the numbers of undetected cancers. Each endoscopy service will be able to review their own cases and so see what specific issues are present in their unit.

Using these findings to improve endoscopy services could mean more than 850 bowel cancer cases each year in England could be diagnosed earlier, or even prevented by removing pre-cancerous polyps. As well as saving lives, this could save the NHS over £7 million.

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