Can using information about people’s genes improve bowel cancer screening?
Bowel cancer screening saves lives, but how can it be improved even more? Dr Juliet Usher-Smith and her team are investigating if using information about ‘risk factors’ - things we know can increase risk of bowel cancer (like changes to genes (mutations) and diet) - could help better decide when people should be invited for bowel screening, what type of screening they should have and how often they should be invited.
The results of a study by the team, which we funded, have now been published in the journal Cancer Prevention Research. We asked Dr Usher-Smith and Dr Catherine Saunders, who is lead author on this work, about the key findings and to explain what’s next.
How does bowel cancer screening work at the moment?
Screening is a way of testing healthy people to see if they show any early signs of cancer. At the moment, everyone aged 60-74 (50-74 in Scotland) is invited to take part in bowel cancer screening, regardless of other risk factors they might have.
What did the research involve?
First we searched in the medical literature for studies that had developed ways of combining changes in genes and other risk factors into ‘models’ that estimate a persons’ risk of developing bowel cancer. In that study, also funded by Bowel Cancer UK, we found 29 models.
In this research, we wanted to find out how good these models are at finding people in the UK who go on to develop bowel cancer and if including information on changes to genes, with or without other factors, could therefore be used to tailor the screening programme. For example, people at higher or lower risk of the disease could be invited to take part at different ages, have screening more or less often or have a different type of test. This is called risk-stratified screening.
It is thought that inviting people to take part in screening based on their individual risk might pick up a greater number of cancers at an early stage, as well as improve the cost-effectiveness of the screening programme for the NHS.
We tested 23 of the 29 models we found using data from nearly half a million people in the UK Biobank – a ‘bank’ of information and samples (such as blood, urine and saliva) from people who have agreed to have their health followed over time.
Using this bank of information, we looked at how well these risk models could predict who would go on to develop bowel cancer, based on information about changes in genes (mutations) and lifestyle factors (like diet and physical activity).
What did you find?
This study is the first to compare lots of risk models in a UK population in this way. Compared to the current screening programme (which only uses age as a factor to decide who should be invited), this research suggests that including information about genes that could increase risk could better predict who was likely to develop bowel cancer. Including information about lifestyle factors too meant they were slightly better still at identifying people who may get the disease.
Including more tailored information about bowel cancer risk could make the screening programme more effective and ultimately mean more lives are saved.
The study suggests the Bowel Cancer Screening Programme should consider including lifestyle and genetic information so that invitations to join the screening programme are tailored based on a person’s risk. But we’re not quite ready for this yet.
Although this research is a step towards a more personalised approach to screening, there is still more work to be done. Future research should look at the costs as well as exploring more about the potential benefits to the public of changing to a risk-stratified screening programme. This is something we’re working on now.
Future work also needs to understand some of the practical and ethical issues of collecting people’s genetic information, to make sure that everyone has equal access to genetic testing and the information is used appropriately.
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Dr Catherine Saunders and Dr Juliet Usher-Smith