Real-World Performance of FIT Triage for Symptomatic Colonoscopy: Analysis of the UK National Endoscopy Database (NED).

BACKGROUND

The UK has adopted faecal immunochemical testing (FIT) to triage symptomatic colonoscopy referrals.

OBJECTIVE

Quantify diagnostic yield and independent effects of FIT, age, sex and symptoms on polyp and cancer detection in symptomatic colonoscopy.

DESIGN

Nationwide analysis of prospectively collected colonoscopy reports (June 2023-August 2025) from the National Endoscopy Database. Symptomatic procedures, including iron-deficiency anaemia (IDA), were identified and diagnostic yields calculated. Mixed-effects logistic regression estimated adjusted odds ratios (aORs) with age, sex, symptom group and FIT. Post-estimation margins modelled cancer yield by age, FIT and symptoms.

RESULTS

Analysis of 447,109 symptomatic colonoscopies, with FIT recorded in 202,219 (45.2%). Overall cancer yield was 1.9% (95% CI, 1.8-1.9). Cancer yield was 3.8% (95% CI, 3.7-3.9) in FIT ≥ 10, including 2.5% (95% CI, 2.3-2.7) at age 40-49 and 0.6% (95% CI, 0.5-0.7) at age 16-39; yield in FIT < 10 was 0.3% (95% CI, 0.2-0.3). FIT concentration showed a strong, graded association with cancer risk, weaker association with large polyps, and minimal association with small polyps. IDA was associated with higher cancer risk versus rectal bleeding (aOR 2.2, 95% CI, 2.0-2.3; p < 0.01). With FIT < 10, cancer yield exceeded 1% only in IDA patients aged > 80 and remained < 0.5% otherwise. A model combining FIT, age, and IDA detected > 94% of cancers while reducing colonoscopy demand by > 40%.

CONCLUSION

This national analysis demonstrates the superiority of FIT-based triage over symptom-based referral, with FIT ≥ 10 identifying high-risk patients, including those aged 40-49, while FIT < 10 indicated very low risk.