O228: Do additional faecal immunochemical tests (FIT) provide more reassurance that colorectal cancer is not being missed? Results from the repeat FIT (RFIT) study

Abstract Introduction Faecal immunochemical testing (FIT) is highly sensitive for colorectal cancer (CRC) detection. NICE recommend a single FIT in primary care for urgent cancer referrals. Little evidence regarding the benefit of repeating FIT exists. The repeat FIT (RFIT) study aims to determine whether second and third FIT provide reassurance and improve CRC or significant bowel disease (SBD) identification. Methodology Prospective observational cohort study (UK HRA and REC approval). Patients recruited from urgent referrals returned three FIT and underwent colonoscopy. χ2 test compared categorical data. Accuracy (sensitivity/specificity/PPV/NPV) reported for one, two and three FIT (95% CI). Three negative FIT (<10µg Hb/g) cohorts (single, double, triple) were compared with positive cohorts (one or more FIT ≥10µg Hb/g). SBD and CRC detection rates were compared by strategy. Median FIT was calculated for pathology. Results 460 patients included (mean age=66.8yrs, M:F 233:227, CRC=23, SBD=80). For single, double and triple negative FIT, CRC sensitivity remained static (95.7%), specificity (44.6%,40.7%,38.4%) and NPV decreased (99.5%,99.4%,99.4%). For SBD, sensitivity increased (78.8%,83.8%,86.3%), specificity decreased (47.4%,43.7%,41.6%) and NPV increased (91.4%,92.7%,93.5%). In single, double and triple positive FIT cohorts, CRC detection was 8.3%,16.1%, 20.9%. CRC mean FIT was 150µg Hb/g, <6 for benign pathology. Conclusion The presence of negative FIT (single/multiple) reduces likelihood of CRC/SBD. Multiple FIT strategy provides greater differentiation and improved CRC/SBD detection compared to single FIT. Repeat FIT offers a safe, cost-effective strategy for triaging symptomatic patients. This may provide reassurance, or safely allow investigation on non-urgent pathways.