‘Low’ faecal immunochemical test (FIT) colorectal cancer: a 4-year comparison of the Nottingham ‘4F’ protocol with FIT10 in symptomatic patients

Bailey, J A; Morton, A J; Jones, J; Oliver, S; Morling, J R; Patel, H; Humes, D J; Banergee, A

Abstract

Aim:

To evaluate colorectal cancer outcomes after “low” (sub-threshold) Faecal Immunochemical Test (FIT) results in symptomatic patients tested in primary care.

Method:

Retrospective audit of 35,289 patients with FIT results, having consulted their general practitioner with lower gastrointestinal symptoms, and subsequent colorectal cancer (CRC) diagnoses. The Rapid Colorectal Cancer Diagnosis pathway was introduced in November 2017 to allow incorporation of FIT into clinical practice. The local “4F” protocol combined FIT results with blood tests and digital rectal examination (DRE): FIT, Full blood count (FBC), Ferritin and Finger.

Outcome:

Detection rates of CRC, missed CRC and time to diagnosis in local “4F” protocols for patients with a sub-threshold faecal Haemoglobin (fHb) result compared to thresholds of 10 and 20µgHb/g Faeces.

Results:

A single threshold of 10 µgHb/g Faeces identifies a population in whom the risk of CRC is 0.2% but would have missed 63 (10.5%) of 599 CRCs in this population. The Nottingham “4F” protocol would have missed fewer CRCs (42 of 599 (7%)) despite using a threshold of 20 µgHb/g Faeces for patients with normal blood tests. Subthreshold FIT results in patients subsequently diagnosed with a palpable rectal tumour yielded the longest delays.

Conclusion:

Combination of FIT with blood results and DRE (“4F”) reduced the risk of missed or delayed diagnosis. Further studies on the impact of such protocols on the diagnostic accuracy of FIT are expected. The value of adding blood tests to FIT may be restricted to specific parts of the fHb result spectrum.

Citation

Bailey, J. A., Morton, A. J., Jones, J., Oliver, S., Morling, J. R., Patel, H., …Banergee, A. (2024). ‘Low’ faecal immunochemical test (FIT) colorectal cancer: a 4-year comparison of the Nottingham ‘4F’ protocol with FIT10 in symptomatic patients. Colorectal Disease, 26(2), 309-316. https://doi.org/10.1111/codi.16848

• Journal Article Type: Article
• Acceptance Date: Nov 20, 2023
• Online Publication Date: Jan 3, 2024
• Publication Date: 2024-02
• Deposit Date: Nov 27, 2023
• Publicly Available Date: Nov 30, 2023
• Journal: Colorectal Disease
• Print ISSN: 1462-8910
• Electronic ISSN: 1463-1318
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 26
• Issue: 2
• Pages: 309-316
• DOI: https://doi.org/10.1111/codi.16848
• Keywords: Colorectal Cancer, Faecal Immunochemical Testing, Blood tests, Digital rectal
• Public URL: https://nottingham-repository.worktribe.com/output/27858416
• Publisher URL: https://onlinelibrary.wiley.com/journal/14631318