THE ROLE OF FIT IN TRIAGING COLONOSCOPY REQUESTS: LESSONS LEARNT DURING FIRST WAVE OF COVID

IntroductionThe role of faecal immunochemical testing (FIT) in the symptomatic pathway for suspected colorectal cancer (CRC) has been growing in importance. NICE guidance (NG 12) recommends using FIT in the diagnostic pathway to assess for CRC in adults with low risk of CRC (≥ 50 years with change in bowel habit (CIBH) or iron deficiency anaemia (IDA) and no rectal bleeding;or ≥ 60 years with anaemia with no rectal bleeding). Owing to increasing pressure on endoscopy services over the last few years, the role of FIT as a tool for triaging colonoscopy referrals has been growing in importance. This has been particularly pertinent over the COVID-19 coronavirus pandemic period where endoscopy services have been severely affected. We present our experience of the use of FIT in the symptomatic CRC pathway over the initial COVID-19 coronavirus wave (April-July 2020).MethodsFIT was introduced into our service in late April 2020 and was used to triage and manage patients who had been placed on a waiting list when endoscopy services ceased at the end of March 2020 during the first wave of COVID-19 coronavirus. All patients referred into the symptomatic CRC pathway underwent investigations (colonoscopy/CTC) as we wanted to understand and audit the impact of FIT on outcomes. A lower FIT cut-off of 4μg/g was used for triage, based on DG30 data (NICE NG12) for the OC Sensor assay. Patients with FIT < 4μg/g were deemed at very low risk of malignancy and underwent a non-urgent colonoscopy or CTC. All patients with FIT > 4μg/g were prioritised for colonoscopy or urgent CTC during the initial recovery phase of our colonoscopy services in May 2020. Colonoscopy and CTC activity from April to July 2020 through the CRC pathway was retrospectively analysed.ResultsBetween May-July 2020, 751 patients (393 females, 358 males, mean age 64 years) underwent lower gastrointestinal endoscopy (606 colonoscopy, 145 flexible sigmoidoscopy). 477 patients with low-risk CRC history were triaged using FIT. 359 (75%) of patients with FIT< 4μg/g underwent non-urgent colonoscopy and none of these patients had CRC diagnosed at colonoscopy. Out of 73 CRC diagnosed during April-July 2020, 8 (11%) were in the FIT group and 5 (63%) had FIT levels of 400μg/g (χ2, df=1, n=477), 6.54, p=0.01, and underwent urgent colonoscopy that led to diagnosis. Three of these patients had FIT < 4μg/g and underwent non-urgent colonoscopy at a mean of 8 weeks after their FIT test. FIT < 4μg had a sensitivity of 62.5%, a specificity of 77%, a PPV of 4.3% and an NPV of 99.2% in our series. In the CTC group, 18/23 (78%) had FIT < 4μg and none of the patients in this group had CRC on imaging.15 patients were admitted during the first COVID-19 coronavirus wave with bowel obstruction and underwent successful urgent colonic stenting due to suspension of the CRC surgical pathway at the time. FIT has now been incorporated into our symptomatic suspected CRC pathway.ConclusionsOur data confirms the utility of FIT in triaging patients for CRC and highlights our successful triage strategy using FIT to inform prioritising procedures during the first wave of the COVID-19 coronavirus pandemic.