A randomised comparison of two faecal immunochemical tests in population-based colorectal cancer screening

Objective Colorectal cancer screening programmes are implemented worldwide; many are based on faecal immunochemical testing (FIT). The aim of this study was to evaluate two frequently used FITs on participation, usability, positivity rate and diagnostic yield in population-based FIT screening. Design Comparison of two FITs was performed in a fourth round population-based FIT-screening cohort. Randomly selected individuals aged 50-74 were invited for FIT screening and were randomly allocated to receive an OC -Sensor (Eiken, Japan) or faecal occult blood (FOB)-Gold (Sentinel, Italy) test (March-December 2014). A cut-off of 10 mg haemoglobin (Hb)/g faeces (ie, 50 ng Hb/mL buffer for OC-Sensor and 59 ng Hb for FOB-Gold) was used for both FITs. Results In total, 19 291 eligible invitees were included (median age 61, IQR 57-67; 48% males): 9669 invitees received OC-Sensor and 9622 FOB-Gold; both tests were returned by 63% of invitees (p = 0.96). Tests were non-analysable in 0.7% of participants using OC-Sensor vs 2.0% using FOB-Gold (p < 0.001). Positivity rate was 7.9% for OC-Sensor, and 6.5% for FOB-Gold (p = 0.002). There was no significant difference in diagnostic yield of advanced neoplasia (1.4% for OC-Sensor vs 1.2% for FOB-Gold; p = 0.15) or positive predictive value (PPV; 31% vs 32%; p = 0.80). When comparing both tests at the same positivity rate instead of cut-off, they yielded similar PPV and detection rates. Conclusions The OC-Sensor and FOB-Gold were equally acceptable to a screening population. However, FOB-Gold was prone to more non-analysable tests. Comparison between FIT brands is usually done at the same Hb stool concentration. Our findings imply that for a fair comparison on diagnostic yield between FIT's positivity rate rather than Hb concentration should be used.