Bowel cancer screening samples could also be used for crucial research into other major health conditions, a new study has shown.
Around half a million samples are collected from over-50s in Scotland each year in a highly successful NHS programme that significantly boosts early cancer detection.
But only a tiny amount of the sent-in poo – mixed with fluid - is needed to test for traces of blood and the rest is discarded.
Now scientists at the Rowett Institute, University of Aberdeen, have demonstrated the discarded part could instead be used for DNA testing, offering “unparalleled statistical power” to assess links between the gut microbiota and some of the most prevalent causes of poor health, including cardiovascular disease, chronic inflammatory disease and diabetes.
It could also offer “vital insights into the gut microbiota during cancer development and treatment response”. In the longer term, there may be clinical trials of interventions aimed at altering the gut microbiota to improve clinical outcomes in such diseases.
“An ability to reliably measure gut microbiota composition in surplus qFIT samples…could lead to large-scale, low-cost, population-based studies,” the team concludes in a paper published in the Microbial Genomics journal.
“Given the challenges of collecting, storing, processing and comprehensively assessing the gut microbiota using larger volume/whole stool samples…the utility of such an acceptable, easy to use, reliable and reproducible method of sampling which already has widespread clinical use cannot be understated.”
NHS Grampian Biorepository, the Universities of Glasgow and Edinburgh and Biomathematics & Statistics Scotland were partners in the study, which was funded by NHS Grampian Charity.
It is believed to be the first to examine the potential of samples gathered with the specific type of qFIT system used in Scotland – which is also used in Ireland, Wales, Japan and Taiwan and for symptomatic testing by some NHS trusts in England.
In our laboratory, when sampling volunteer stool samples with qFIT probes, we found that samples remained stable over 14 days and were very similar to larger stool control samples.
Prof Anne Kiltie, Friends of ANCHOR Clinical Chair in Oncology at the Rowett Institute, said: ‘We are thrilled that the tiny amounts of poo (2 mg) in the qFIT cassettes can give us so much reliable information about the bacteria in the gut.
“We now want to conduct much larger studies in common diseases with big impacts on people’s lives. We need to engage with patient and public partners and relevant agencies to design the studies and then obtain substantial grant funding to undertake this work.”
Prof Chris Halsey, Head of the School of Cancer Sciences, University of Glasgow commented: “This innovative research means that we can maximise the value of bowel screening tests to not only detect cancer but also understand better the link between gut bacteria and a wide range of health challenges facing the Scottish population.”
Lisa Duthie, NHS Grampian Charity Lead, said: "This research is a really encouraging step forward for people living with chronic health conditions.
"Innovative thinking, like expanding the use of bowel cancer screening samples, is essential to develop new diagnostic tools and treatment options for patients in the future, and we are grateful to our generous supporters who help us fund exciting new research like this."