TBA (25S162)

FIT Testing In The Symptomatic Population; Is It FIT For Purpose? A Multi-centre Retrospective Study Of Colonoscopy Outcomes In Low Risk Patients Undergoing FIT Testing In Ireland

Author(s)

E. Mech 1; T. J. Matthews 2; A. Harrison 3; C. Steele 3; M. Mc Nally 4; E. Myers 5; J. Leyden 2,18; G. Doherty 6,18; S. V. Johnson 6; S. Draper 2; S. O’Kane 3; A. M. Cahill 4; G. McLoughlin 5; J. O'Grady 7; F. Aftab 8; D. Schmidt 8; A. Ireland 9; G. Horgan 10; G. Courtney 11; M. Buckley 12; C. K. Shahzad 12; D. McNamara 13; W. Swati 14; F. Cooke 15; R. Stack 16; K. Mealy 17; D. Murray 18; L. Byrne 18; C. Hayes 7; M. Macpherson 8; U. Cashman 9; S. Kuttai 10; M. O'Sullivan 11; L. Franklin 12; E. Omallao 13; J. Kelly 14; L. Hurley 15; M. O'Connor 16; M. Lynch 16; H. Neville 16; C. Lynam 17.

Department(s)/Institutions

1 UCD School of Medicine, Dublin, Ireland 2 Mater Hospital, Dublin, Ireland 3 Letterkenny University Hospital, Ireland 4 Midland Regional Hospital Tullamore, Ireland 5 Portiuncula University Hospital, Ireland 6 St. Vincent's University Hospital, Ireland 7 Cork University Hospital, Ireland 8 Mallow General Hospital, Ireland 9 South Infirmary Victoria University Hospital, Ireland 10 St. Columcille's Hospital, Ireland 11 St. Luke’s Hospital, Kilkenny, Ireland 12 St. Michael's Hospital, Dun Laoghaire, Ireland 13 Tallaght University Hospital, Ireland 14 Tipperary University Hospital, Ireland 15 University Hospital Waterford, Ireland 16 University of Limerick Hospital Group, Ireland 17 Wexford General Hospital, Ireland 18 HSE Endoscopy Programme

Introduction

Fecal Immunochemical Test (FIT) with a lower cut-off (50ng/ml) has been proposed as a tool to aid triage of referrals that do not meet criteria for urgent colonoscopy, potentially allowing colonoscopy to be avoided.

Aims/Background

Evaluation of FIT-centered triage approach and suitability as a ‘rule out’ test for colorectal cancer (CRC).

Method

Analysis of FIT testing performed in 7400 symptomatic patients in Ireland (2023-2024). Retrospective analysis was performed in selected centres using FIT-centered triage approach for colonoscopy prioritization from routine (P2) colonoscopy listing.

Results

Of 7,400 patients who underwent FIT testing across 16 sites, 16.4% (n=1,215) had a positive result (FIT≥50ng/mL). Multivariate analysis showed that increased age (OR = 1.029; 95% CI = 1.025-1.033; p-value<0.001) and male sex (OR = 1.44; 95% CI = 1.273-1.63; p-value<0.001) were significantly associated with positive FIT results. At five sites, 1,815 patients who underwent FIT testing were referred for colonoscopy. At these sites, 79.0% (n=1,433) had a FIT<50ng/mL of whom 0.14% (n=2) had CRC and 1.5% (n=21) had other significant findings at colonoscopy (ex: CRC or IBD). In contrast, 21.0% (n=382) had a FIT≥50ng/mL of whom 6.8% (n=26) had CRC and 19.1% (n=73) had significant findings at colonoscopy (ex: CRC or IBD). The proportion of patients with CRC was significantly greater when FIT≥50ng/mL compared to FIT<50ng/mL (Fisher’s Exact Test, p-value <0.001). The sensitivity, specificity, and negative predictive value of FIT<50ng/mL for colorectal at subsequent colonoscopy is 92.9% (95%CI=75.0-98.8%), 80.1% (95%CI=78.1-81.9%), and 99.9% (95%CI=99.4-99.9%), respectively.

Conclusions

FIT-centered triage is useful in low-risk symptomatic patients referred for colonoscopy and has very good negative predictive value for colorectal cancer.