The American Society of Colon and Rectal Surgeons 2021 Annual Scientific Meeting Abstracts

Abstract

Purpose/Background: Faecal immunochemical test (FIT) is widely adopted for the screening of colorectal cancer in the United Kingdom. At the start of the coronavirus pandemic we incorporated FIT testing into our department's urgent referral pathway for patients with suspected colorectal cancer. This aimed to triage those symptomatic patients who required urgent investigation and those who were unlikely to have significant colorectal pathology and therefore could have investigations delayed until it was safer and endoscopy services had recovered capacity. This study aimed to identify the diagnostic accuracy of FIT in this setting. Methods/Interventions: Patients referred to our institution under our urgent cancer referral pathway between 28th April and 19th June 2020 were identified from a prospectively kept database. FIT results were accessed from electronic laboratory records. Results were analysed using a threshold of 10ug/ml and the current screening threshold in England of 120ug/ml. Patient outcomes were determined by electronic patient records. Significant polyps included polyps greater than 10mm or meeting British Society of Gastroenterology high risk criteria. Results/Outcome(s): 373 patients were referred to the colorectal department during the study period. 24 referrals did not meet urgent referral criteria. 202 (54%) patients had FIT performed by their general practitioner and 47 (13%) patients had FIT undertaken in the colorectal clinic. In patients who had FIT, 97 (41%) patients had a FIT result less than 10ug/ml and 193 (81%) patients had FIT less than 120ug/ml. 25 (10%) patients were not investigated further based on FIT result and 16 (6%) patients declined further investigation. 13 (3%) patients in the cohort were subsequently investigated and diagnosed with a colorectal cancer (FIT range 24-8438ug/ml). One patient was diagnosed with a gastric cancer (FIT 259ug/ml) and two other patients had incidental findings of other nongastrointestinal cancers. 9 (4%) and 19 (8%) patients had significant colonic polyps and colitis respectively. Other diagnoses included bleeding gastric ulcer (2), angiodysplasia (1) and solitary rectal ulcer syndrome (1). In this symptomatic cohort, with a threshold of 10ug/ml the sensitivity of FIT was 100% and specificity of 36% for the diagnosis of colorectal cancer. At the 120ug/ml threshold the sensitivity was 77% and the specificity 81% for the diagnosis of colorectal cancer. Conclusions/Discussion: Incorporating FIT to triage symptomatic patients with symptoms suggestive of colorectal cancer is feasible with acceptable levels of diagnostic accuracy when utilizing a threshold of 10ug/ml. FIT testing will continue to be incorporated into our urgent cancer referral pathway, although general practitioners may still refer patients with a negative FIT but high clinical suspicion. Further work will continue to audit the use of FIT in this symptomatic setting.