The study, published in Cancer Prevention Research journal, compared the current bowel cancer screening programme in England – where people are invited for screening based on their age alone – to a strategy that starts screening at variable ages determined through a risk assessment from the age of 40.

Researchers looked at data from 6,787 patients who took part in the Health Survey for England, as well as multiple other databases, to create a model that simulates the life course of people over the age of 30 in England with varying levels of risk of bowel cancer. The model includes data on the individuals’ lifestyle behaviours, family history and any genetic changes associated with bowel cancer, as well as population-wide data for the disease, like incidence and survival.

This model was then used to calculate whether screening people based on their estimated risk of bowel cancer would reduce the number of bowel cancer cases, deaths and costs compared to starting screening for everyone at 60, the current age the bowel cancer screening programme starts in England. NHS England have announced the screening age will be gradually lowered to 50 from April 2021, as part of the NHS Long Term Plan.

The team of researchers predict that using this approach could result in 218 fewer bowel cancer cases and 156 fewer deaths per 100,000 people.

The financial benefits depend on how much it will cost to estimate the risk of bowel cancer in everyone aged 40 and over. The study suggests that determining a person’s likelihood of developing bowel cancer through a risk assessment could cost the NHS up to £114 per person and the overall programme still be more cost effective than the current screening programme.

One way to determine an individual’s risk of bowel cancer in a cost effective way could be to combine collecting patient data, such as their lifestyle and genetic risk factors for bowel cancer, with data that is already routinely collected in primary care.

Bowel cancer is the UK’s second biggest cancer killer, but it shouldn’t be as it’s treatable and curable especially if diagnosed early. Taking part in screening is one of the best ways to be diagnosed at an early stage, when treatment is more likely to be successful.

Genevieve Edwards, Chief Executive of Bowel Cancer UK, said: “This important research that we’ve funded helps add to the evidence that screening people based on their risk of developing bowel cancer is more effective in detecting the disease earlier, could prevent some cancers from developing and ultimately save more lives. It may mean that some individuals with a low risk of having bowel cancer may be screened later, compared to someone else who has a higher risk of the disease – making it cost effective for the NHS.

“We know the number of under 50s with bowel cancer continues to slowly rise, so identifying those at greater risk of the disease could help the NHS to determine which patients could benefit from screening at a younger age.

“While screening is undoubtedly one of the best ways to diagnose bowel cancer at an early stage, anybody with symptoms, including bleeding from your bottom, blood in your poo, a persistent change in bowel habits, unexplained weight loss, extreme tiredness for no obvious reason and a pain or lump in your tummy, should always contact their GP as soon as possible.”

Using estimated risk rather than just age to determine when people are first invited to screening has the potential to be a fairly resource-neutral means of improving the effectiveness of the screening programme. This is particularly important in England where one of the biggest limitations to expanding the programme is lack of more screening capacity.”

– Juliet Usher-Smith, University Lecturer in General Practice, University of Cambridge

Chloe Thomas, research fellow and lead health economic modeller on the project at the University of Sheffield, says: “Identifying those most at risk of bowel cancer and screening them earlier than those less at risk is a way of potentially improving both the effectiveness and the efficiency of the bowel cancer screening programme, particularly if it remains infeasible due to resource constraints, to screen everyone from a younger age.”

Additional research by the research team funded by Bowel Cancer UK and the National Screening Committee, which was published earlier this year in Cancer Prevention Journal, suggests that inviting men before women would also be more cost effective. For example, if men were invited to start bowel cancer screening at the age of 56 and women at 60, this may result in fewer bowel cancer cases, especially at a later stage, as well as fewer deaths, per 100,000 people living in England. However, the research did highlight that the benefits of this would be negligible once the screening age is reduced to 50 for both men and women – a key way of reducing cases and deaths.

Read the research

The costs and benefits of risk-stratification for colorectal cancer screening based on phenotypic and genetic risk: a health economic analysis. Chloe Thomas, Olena Mandrik, Catherine L. Saunders, Deborah Thompson, Sophie Whyte, Simon Griffin, Juliet A. Usher-Smith. May 26 2021. Cancer Prev Research.