title: Screening for colorectal cancer: random comparison of guaiac and immunochemical faecal occult blood testing at different cut-off levels.
abstract: Immunochemical faecal occult blood testing (FIT) provides quantitative test results, which allows optimisation of the cut-off value for follow-up colonoscopy. We conducted a randomised population-based trial to determine test characteristics of FIT (OC-Sensor micro, Eiken, Japan) screening at different cut-off levels and compare these with guaiac-based faecal occult blood test (gFOBT) screening in an average risk population. A representative sample of the Dutch population (n=10 011), aged 50-74 years, was 1 : 1 randomised before invitation to gFOBT and FIT screening. Colonoscopy was offered to screenees with a positive gFOBT or FIT (cut-off 50 ng haemoglobin/ml). When varying the cut-off level between 50 and 200 ng ml(-1), the positivity rate of FIT ranged between 8.1% (95% CI: 7.2-9.1%) and 3.5% (95% CI: 2.9-4.2%), the detection rate of advanced neoplasia ranged between 3.2% (95% CI: 2.6-3.9%) and 2.1% (95% CI: 1.6-2.6%), and the specificity ranged between 95.5% (95% CI: 94.5-96.3%) and 98.8% (95% CI: 98.4-99.0%). At a cut-off value of 75 ng ml(-1), the detection rate was two times higher than with gFOBT screening (gFOBT: 1.2%; FIT: 2.5%; P<0.001), whereas the number needed to scope (NNscope) to find one screenee with advanced neoplasia was similar (2.2 vs 1.9; P=0.69). Immunochemical faecal occult blood testing is considerably more effective than gFOBT screening within the range of tested cut-off values. From our experience, a cut-off value of 75 ng ml(-1) provided an adequate positivity rate and an acceptable trade-off between detection rate and NNscope.
authors.affiliation: Department of Gastroenterology and Hepatology, Erasmus MC, University Medical Centre, Rotterdam, The Netherlands. l.hol.1@erasmusmc.nl
authors.forename: L
authors.initials: L
authors.lastname: Hol
authors.forename: J A
authors.initials: JA
authors.lastname: Wilschut
authors.forename: M
authors.initials: M
authors.lastname: van Ballegooijen
authors.forename: A J
authors.initials: AJ
authors.lastname: van Vuuren
authors.forename: H
authors.initials: H
authors.lastname: van der Valk
authors.forename: J C I Y
authors.initials: JC
authors.lastname: Reijerink
authors.forename: A C M
authors.initials: AC
authors.lastname: van der Togt
authors.forename: E J
authors.initials: EJ
authors.lastname: Kuipers
authors.forename: J D F
authors.initials: JD
authors.lastname: Habbema
authors.forename: M E
authors.initials: ME
authors.lastname: van Leerdam