Risk-stratified faecal immunochemical testing (FIT) for urgent colonoscopy in Lynch syndrome during the COVID-19 pandemic

Abstract

Background: Lynch syndrome is a hereditary cancer disease resulting in an increased risk of colorectal cancer. Herein, findings are reported from an emergency clinical service implemented during the COVID-19 pandemic utilizing faecal immunochemical testing ('FIT') in Lynch syndrome patients to prioritize colonoscopy while endoscopy services were limited.

Methods: An emergency service protocol was designed to improve colonoscopic surveillance access throughout the COVID-19 pandemic in England for people with Lynch syndrome when services were extremely restricted (1 March 2020 to 31 March 2021) and promoted by the English National Health Service. Requests for faecal immunochemical testing from participating centres were sent to the National Health Service Bowel Cancer Screening South of England Hub and a faecal immunochemical testing kit, faecal immunochemical testing instructions, paper-based survey, and pre-paid return envelope were sent to patients. Reports with faecal haemoglobin results were returned electronically for clinical action. Risk stratification for colonoscopy was as follows: faecal haemoglobin less than 10 µg of haemoglobin/g of faeces (µg/g)-scheduled within 6-12 weeks; and faecal haemoglobin greater than or equal to 10 µg/g-triaged via an urgent suspected cancer clinical pathway. Primary outcomes of interest included the identification of highest-risk Lynch syndrome patients and determining the impact of faecal immunochemical testing in risk-stratified colonoscopic surveillance.

Results: Fifteen centres participated from June 2020 to March 2021. Uptake was 68.8 per cent amongst 558 patients invited. For 339 eligible participants analysed, 279 (82.3 per cent) had faecal haemoglobin less than 10 µg/g and 60 (17.7 per cent) had faecal haemoglobin greater than or equal to 10 µg/g. In the latter group, the diagnostic accuracy of faecal immunochemical testing was 65.9 per cent and escalation to colonoscopy was facilitated (median 49 versus 122 days, χ2 = 0.0003, P < 0.001).

Conclusion: Faecal immunochemical testing demonstrated clinical value for Lynch syndrome patients requiring colorectal cancer surveillance during the pandemic in this descriptive report of an emergency COVID-19 response service. Further longitudinal investigation on faecal immunochemical testing efficacy in Lynch syndrome is warranted and will be examined under the 'FIT for Lynch' study (ISRCTN15740250).

Fig. 1

Flow chart depicting risk-stratified colonoscopy referral design using faecal haemoglobin of greater than or equal to 10 µg/g to indicate a positive test in a cohort of Lynch syndrome patients who returned a faecal immunochemical testing kit as part of this emergency clinical service *Of the 235 participants triaged via Group 1 (f-Hb less than 10 µg/g), 2 were referred for and completed flexi-sigmoidoscopy and 1 had a CT colonography likely due to resource limitations and/or participant tolerance. LS, Lynch syndrome; FIT, faecal immunochemical testing; NHS, National Health Service; f-Hb, faecal haemoglobin.

Fig. 2

Receiver operating characteristic (ROC) curve depicting the performance of faecal immunochemical testing at various faecal immunochemical testing thresholds Area under the curve = 0.66 (95% c.i. 0.53,0.79).

Fig. 3

Kaplan–Meier curves a Line graph with survivals calculated by utilising the Kaplan–Meier (KM) method to examine the proportion of participants by FIT result (f-Hb less than 10 µg/g versus f-Hb greater than or equal to 10 µg/g) who completed colonoscopy within 120 days from time of FIT dispatch. b Line graph with survivals calculated by utilising the KM method to examine the proportion of participants who completed colonoscopy within 120 days from time of FIT dispatch by the following FIT thresholds: f-Hb less than 6 µg/g; f-Hb 6 to less than 10 µg/g; and f-Hb greater than or equal to 10 µg/g. FIT, faecal immunochemical testing; f-Hb, faecal haemoglobin.