Faecal immunochemical test (FIT) based prioritisation of new patient symptomatic cases referred for colorectal investigation.

Abstract

Aim: Quantitative faecal haemoglobin (fHb) measurement by faecal immunochemical test (FIT) is a powerful biomarker for colorectal cancer (CRC) and is incorporated in referral, prioritisation and triage protocols for symptomatic cases in other countries. We report our use of FIT to prioritise new patient symptomatic cases referred for colorectal investigation.

Method: Cases referred for investigation of new colorectal symptoms who were aged ≥50 years (≥40 years Māori/Pacific peoples), who would otherwise be triaged to non-urgent colonoscopy, were asked to provide a stool sample for FIT. Following FIT testing, cases were re-triaged to either urgent colonoscopy, non-urgent colonoscopy or computed tomography colonography (CTC) depending on fHb concentration (measured in micrograms haemoglobin per gram of stool [mcg/g]) and incorporating clinical judgement. At pathway initiation, cases already waiting for colonoscopy on the non-urgent new patient waiting list were approached first, and then new patient (NP) referrals for colonoscopy could be triaged to the pathway at the discretion of the triaging consultant.

Results: Out of 739 cases, 715 (97%) returned FIT samples, and 691 cases completed colorectal investigations. Overall FIT positivity ≥10mcg/g was 17.1%. Fifteen colorectal cancers (CRC) were detected (2.2%). The sensitivity and specificity of FIT ≥10mcg/g for CRC were 80.0% (54.0-93.7%) and 84.3 (81.4-86.9%) respectively. A total of 432 cases (62.5%) completed the pathway without recourse to colonoscopy, and the median time to CRC diagnosis for NP from referral was 25 days.

Conclusion: FIT based prioritisation of cases referred with symptoms concerning for CRC is feasible and reduces time to CRC diagnosis.