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Faecal Immunochemical Testing (FIT) in patients with signs or symptoms of suspected colorectal cancer (CRC): A joint guideline from the Association of Coloproctology of Great Britain & Ireland (ACPGBI) and the British Society of Gastroenterology (BSG)

Authors (Guideline development group (GDG))

Kevin J Monahan / Michael M. Davies (Co-chairs, and lead authors).
Co-authors: Muti Abulafi, Ayan Banerjea, Brian Nicholson, Ramesh Arasaradnam, Neil Barker, Sally Benton, Richard Booth, David Burling, Rachel Carten, Nigel D’Souza, James East, Jos Kleijnen, Michael Machesney, Maria Pettman, Jenny Pipe, Lance Saker, Linda Sharp, James Stephenson, Robert Steele.

Introduction

Faecal Immunochemical Testing (FIT) has a high sensitivity for the detection of Colorectal Cancer (CRC). In a symptomatic population FIT may identify those patients who require colorectal investigation with the highest priority. FIT offers considerable advantages over the use of symptoms alone, as an objective measure of risk with a vastly superior positive predictive value (PPV) for CRC, whilst conversely identifying a truly low risk cohort of patients. The aim of this guideline was to provide a clear strategy for the use of FIT in the diagnostic pathway of people with signs or symptoms of a suspected diagnosis of CRC. The guideline was jointly developed by the Association of Coloproctology of Great Britain and Ireland (BSG/ACPGBI) British Society of Gastroenterology, specifically by a 21-member multidisciplinary guideline development group (GDG). A systematic review of 13,535 publications was undertaken to develop 23 evidence and expert opinion-based recommendations for the triage of people with symptoms of a suspected CRC diagnosis in primary care. In order to achieve consensus amongst a broad group of key stakeholders, we completed an extended Delphi of the GDG, and also 61 other individuals across the UK and Ireland, including by members of the public, charities, primary and secondary care clinicians. Seventeen research recommendations were also prioritised to inform clinical management.

Please note the guideline will be published in full shortly, however a summary of recommendations and flowchart are presented here to facilitate early implementation. The guidelines will be presented at the annual BSG conference in Birmingham on 21st June 2022. The full guideline is being submitted to Gut where the full references, research implications and appendices will be given including examples of safety netting.

Executive Summary of Recommendations

FIT in Primary Care

1. We recommend that FIT should be used by primary care clinicians to prioritise patients with clinical features of colorectal cancer for referral for urgent investigation
2. We recommend that a FIT threshold of fHb ≥10μg Hb/g should be used in primary care to select patients with lower gastrointestinal symptoms for an urgent referral pathway for colorectal cancer investigation
3. We recommend that patients should not be excluded from referral from primary care for symptoms on the basis of FIT testing alone

Advice for clinicians where patients have not returned a FIT test

4. We suggest that clinicians should follow up patients with no FIT result to encourage them to return a sample or, where the kit has been lost or inadequately submitted, offer a further test
5. We suggest that patients who decline to return a FIT test should be counselled that evaluation of their symptoms is incomplete, and be encouraged to complete their test
6. We suggest that where no FIT result can be obtained, clinicians should use existing national and local guidelines to assess risk of colorectal cancer

Safety Netting

7. We recommend that some patients with symptoms of suspected colorectal cancer may be managed in primary care if fHb <10μg Hb/g, and provided appropriate safety netting is in place
8. We suggest that patients with a fHb <10μg Hb/g but with persistent and unexplained symptoms for whom the GP has ongoing clinical concern should be referred to secondary care for evaluation
9. We recommend that safety netting protocols should incorporate advice and strategies for the diagnosis of colorectal and extra-colonic cancer, as well as other serious gastro-intestinal conditions

Diagnostic accuracy of FIT for CRC with suspected cancer signs or symptoms

10. FIT is a triage tool to identify those patients with symptoms of suspected colorectal cancer who should undergo further colorectal investigation
11. We suggest that FIT be utilised for people with iron deficiency anaemia within primary care to inform urgency of referral
12. We suggest referral of patients with persistent / recurrent anorectal bleeding for flexible sigmoidoscopy if fHb <10μg Hb/g
13. There is currently insufficient evidence to recommend variations in the fHb threshold for referral from primary care according to patient related-factors
14. There is currently insufficient evidence to confirm whether diagnostic accuracy is impacted by the type of FIT analyser used
15. There is currently insufficient evidence to recommend including FIT in a risk score with other clinical features to identify patients with symptoms of suspected colorectal cancer
16. We suggest that FIT may be used to stratify adult patients aged younger than 50 years with bowel symptoms suspicious of a diagnosis of colorectal cancer

Investigation in secondary care

17. Colonoscopy is considered the standard method of investigation, however other methods of colorectal imaging may be appropriate in some patients
18. We recommend that for patients with symptoms of a suspected diagnosis of colorectal cancer, CT Colonography is equivalent to colonoscopy for detection of colorectal cancer (the choice of modality should be determined by the local expertise and availability)
19. There is currently insufficient evidence to support use of a specific quantitative FIT threshold to recommend the selection of CT Colonography versus colonoscopy

Acceptability

20. On the basis of limited evidence, clinicians and patients consider FIT as an acceptable test for symptomatic colorectal cancer in most circumstances
21. We recommend that services should consider ways of promoting a high proportion of patients to return FIT kits

Discrimination

22. We recommend that clinicians actively prevent discrimination at any stage of the diagnostic pathway as symptomatic FIT testing is rolled out, with a focus on equity of access and application to all patients with lower GI symptoms

Implementation

23. We recommend that FIT, as a diagnostic triage tool, can be implemented safely at primary care level, and that a programme of education be developed to facilitate implementation of FIT in primary care