Background: Screening for colorectal cancer (CRC) is widely accepted, but there is no consensus on the preferred strategy. We conducted a randomised trial comparing participation and detection rates (DR) per screenee of guaiac-based faecal occult blood test (gFOBT), immunochemical FOBT (FIT), and flexible sigmoidoscopy (FS) for CRC screening.
Methods: A representative sample of the Dutch population (n=15.011), aged 50-74 years, was 1:1:1 randomised prior to invitation to one of the three screening strategies. Colonoscopy was indicated for screenees with a positive gFOBT or FIT, and for those in whom FS revealed a polyp with a diameter ≥10 mm; adenoma with ≥25% villous component or high grade dysplasia; serrated adenoma; ≥3 adenomas; ≥20 hyperplastic polyps; or CRC.
Results: The participation rate was 49.5% (95% confidence interval(CI) 48.1-50.9%) for gFOBT, 61.5% (CI:60.1-62.9%) for FIT and 32.4% (CI:31.1-33.7%) for FS screening. gFOBT was positive in 2.8%, FIT in 4.8% and FS in 10.2%. The DR of advanced neoplasia was significantly higher in the FIT (2.4%; OR 2.0; CI:1.3-3.1) and the FS arm (8.0%; OR 7.0; CI:4.6-10.7) than the gFOBT arm (1.1%). FS demonstrated a higher diagnostic yield of advanced neoplasia per 100 invitees (2.4; CI:2.0-2.8) than gFOBT (0.6; CI:0.4-0.8) or FIT (1.5; CI:1.2-1.9) screening.
Conclusion: This randomised population-based CRC-screening trial demonstrated superior participation and detection rates for FIT compared to gFOBT screening. FIT screening should therefore be strongly preferred over gFOBT screening. FS screening demonstrated a higher diagnostic yield per 100 invitees than both FOBTs.