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Queen’s researchers highlight wide variation in bowel cancer screening in the UK

Queen’s academics have written a key editorial highlighting new research on bowel cancer rates, published in the British Medical Journal (BMJ).

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A study published in the BMJ highlights a substantial variation between colonoscopy providers in rates of bowel cancer up to three years after routine testing in England. In an accompanying editorial, Queen’s University Belfast researchers highlight this unacceptable variation and emphasise the need for high quality data and investment in data infrastructure to help solve this important public health issue.

The findings of the study show that, reassuringly, the rates of post-colonoscopy bowel cancer have significantly reduced and are now amongst the lowest rates seen worldwide, indicating the overall high quality of camera tests for bowel cancer in England.

What needs addressing is the variation between providers with some having much lower, and some much higher rates. The lowest rates were seen by dedicated bowel cancer screening providers and some of the higher rates by private providers on behalf of the NHS.

By reducing this variation, and lowering rates further, many cancers could be prevented or diagnosed at an earlier stage, say the researchers.

Dr Ethna McFerran, a cancer health economist at Queen’s University Belfast and lead author of the accompanying editorial said: “These studies are a welcome appraisal of screening and colonoscopy performance and show how good quality data can help inform policy. They demonstrate that there is wide variation in bowel cancer rates after routine screening in England; the differences that have been found between public and private providers are worrying but also indicate definite scope for improvement.”

Bowel (colorectal) cancer is a major public health problem in the UK, with over 40,000 new cases diagnosed and 16,000 deaths each year. A person’s risk depends on their age, sex, genetics and lifestyle.

Colonoscopy is the main test for bowel cancer. Like most tests, it is not always 100% accurate and cancers can appear within months or years after a negative result. These are called post-colonoscopy colorectal cancers or PCCRCs.

The British Society of Gastroenterology says PCCRCs should be used as a benchmark for the quality of a colonoscopy service, and the World Endoscopy Organisation (WEO) has recently developed a way to compare performance between providers.

Using this method, a team of UK researchers set out to compare PCCRC rates between all providers in England to measure variation in colonoscopy quality.

Their findings are based on more than 120,000 individuals undergoing colonoscopy in England between 2005 and 2013 and subsequently diagnosed with colorectal cancer. The proportion of those diagnosed six months to three years after the colonoscopy were identified to calculate a PCCRC-3yr rate.

After taking account of potentially influential factors such as age, sex, and medical history, the PCCRC-3yr rate declined from 9.0% in 2005 to 6.5% in 2013.

However, rates for colonoscopies performed within the NHS Bowel Cancer Screening Programme (BCSP) were better (lower) at 3.6% than those performed by independent providers (9.3%) which are increasingly being used to meet the rising demand for colonoscopy.

The researchers say that, if this lower rate had been achieved over the entire study period, “more than 3,900 cases of colorectal cancer could have been prevented or diagnosed earlier.”

Rates were also higher among women, people aged 80 or over, and those with inflammatory bowel disease.

This is an observational study so can’t establish cause, and the researchers point to some limitations in the data, which may have affected the accuracy of the calculations.

Nevertheless, they say this is a large, nationally representative study, and the variation between providers remained after further analyses, suggesting that the findings withstand scrutiny.

They conclude: “PCCRC is largely avoidable and targeted improvement is required to reduce this variation and drive down PCCRC-3yr rates further. This will result in earlier diagnosis and improve mortality from this preventable disease.”

Mark Lawler, Professor of Digital Health at the Centre for Cancer Research & Cell Biology at Queen’s University Belfast, Scientific Director of DATA-CAN, the Health Research Hub for Cancer and Senior Author on the study added: “The research reinforces the need for strategic investment in appropriate data infrastructure, coupled with clear communication with all decision makers, including patients. Initiatives such as the recently announced DATA-CAN, a pan UK Health Data Research Hub for Cancer, help provide the digital framework to ensure that high quality data intelligence underpins improved service development for our citizens and patients.”

“These studies provide important information for policy makers here in Northern Ireland to take on board, particularly in light of the work being carried out on a new cancer strategy for the region.”

Roisin Foster, Chief Executive of Cancer Focus NI, said: “It is gratifying that Dr McFerran and Professor Lawler, whose research is funded by us, were invited by the prestigious BMJ, one of the best medical journals in the world, to give their opinion and critical analysis of this new research. It is a welcome acknowledgement of the high quality and significance of the cutting-edge research being carried out here in Northern Ireland.” 

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Photo: Professor Mark Lawler

Professor Mark Lawler

The Patrick G Johnston Centre for Cancer Research

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