Can microbiome data improve the NHS Bowel Cancer Screening Programme? Sub-study: Investigating the microbiome of people undergoing FIT testing for bowel symptoms

Every year, over two million people in England post a faecal sample card or tube to the NHS as part of the Bowel Cancer Screening Programme. This project asks whether adding data on the bacteria living in those samples—the gut microbiome—could help the screening test catch more cancers and flag fewer false alarms. The current screening test (FIT) looks for hidden blood in stool. It is good but not perfect: some cancers bleed intermittently, and many people with a positive result turn out not to have cancer after a stressful follow-up colonoscopy. The researchers want to know if the microbial DNA already present in those same screening samples can distinguish cancerous from non-cancerous changes more accurately than blood alone. They will also test samples from patients who have bowel symptoms and are referred for FIT testing through a hospital clinic. If microbiome data improves screening accuracy, the NHS could reduce unnecessary colonoscopies, catch cancers earlier, and make the programme more cost-effective—without asking patients to do anything extra. The samples are already collected; the question is whether the information in them is being wasted.