Triaging colorectal urgent referrals in the COVID-19 era using faecal immunochemical testing: a prospective UK...

During the early COVID-19 pandemic, UK guidelines advocated faecal immunochemical tests (FIT) with a threshold of 10 µg/g to help secondary care clinicians triage urgent suspected colorectal cancer (CRC) referrals. We aimed to evaluate the real-world performance and impact of FIT in a high-risk cohort referred against National Institute for Health and Clinical Excellence NG12 (2015) criteria.

Multicentre prospective observational cohort study of FIT at all four secondary care hospitals in Devon (UK) between 1 April 2020 and 31 December 2020. FIT use was at the discretion of primary and secondary care clinicians. Incident CRC cases were identified ≥12 months after general practitioner (GP) referral using regional National Bowel Cancer Audit data linkage. We assessed diagnostic accuracy and healthcare utilisation in patients with and without FIT.

Overall, 6698 patients were included: 55% female, median age 72 years (IQR 65-82). Just over half (53%, 3552) of patients underwent FIT with a positivity rate of 34% (n=1237). CRC prevalence in patients with no FIT, positive FIT and negative FIT was 6% (189), 11% (137) and 0.5% (11), respectively. The prevalence of all cancers, including non-CRCs, was similar among FIT and no-FIT cohorts (p=0.74). Sensitivity and specificity of FIT for CRC were 0.93 (95% CI 0.87 to 0.96) and 0.68 (95% CI 0.66 to 0.69), respectively. Patients with negative FIT underwent fewer lower gastrointestinal endoscopies (no FIT 62% (1964) vs positive FIT 69% (857) vs negative FIT 36% (835)), p=0.0005).

FIT is a useful triage tool for patients with suspected CRC which safely reduces endoscopy demand and prioritises those at greatest cancer risk. Standardised regional referral pathways, greater use of 'straight-to-test' investigations and GP support are needed to maximise its impact.