As bowel cancer screening in England recovers from pandemic suspensions of service, new research suggests that the best option for clearing the backlog of patients awaiting colonoscopy appointments is to raise the blood level on the test that triggers a colonoscopy invitation.
In England, 37 people die each day from bowel cancer, but screening using faecal blood testing followed by colonoscopy can reduce both the incidence of this cancer and the number of resulting deaths. People undergoing NHS bowel cancer screening who have a faecal blood test result above a defined level are invited for a colonoscopy, but two factors - the COVID-19 pandemic, and the introduction of a lower age for people to be invited for this screening - have caused higher demand on colonoscopy appointments. This study, led by WIPH researchers, looked at whether the solution to this problem may be to change either the time span between screening invitations, or the blood level at which the faecal test result triggers a colonoscopy invitation.
Researchers analysed data from 27,238 people aged 59-75 who were screened in the English Faecal Immunochemical Testing pilot study. Results suggest that changing the blood level at which the faecal blood test triggered an invitation to colonoscopy was a more effective tactic than changing the gap between screening invitations. While both methods could reduce the number of colonoscopies, increasing the faecal blood trigger point would result in fewer lives lost than changing the invitation interval.
The study showed that current two-yearly screening with a faecal haemoglobin threshold of 120 μg/g would generate an estimated 16,092 colonoscopies, would detect 1142 colorectal cancers, and prevent 186 colorectal cancers and 191 deaths per 100,000 screened over 15-years. Increasing the faecal haemoglobin threshold to 180 μg/g would reduce required colonoscopies to 11,500, detect 1077 colorectal cancers, and prevent 131 colorectal cancers and 151 deaths. Changing two-yearly screening to three-yearly would reduce required colonoscopies to 10,283, detect 909 colorectal cancers and prevent 126 colorectal cancers and 138 deaths. Increasing the faecal haemoglobin threshold was estimated to be more efficient than increasing the interscreening interval regarding overall colonoscopies per screen-benefited cancer.
The co-authors’ contribution to this work was part-funded by the National Institute for Health Research Policy Research Programme, conducted through the Policy Research Unit in Cancer Awareness, Screening and Early Diagnosis.
Shuping J Li, Tara Seedher, Linda D Sharples, Sally C Benton, Christopher Mathews, Rhian Gabe, Peter Sasieni, Stephen W Duffy. Impact of changes to the interscreening interval and faecal immunochemical test threshold in the national bowel cancer screening programme in England: results from the FIT pilot study. British Journal of Cancer 2012. DOI: 10.1038/s41416-022-01919-y