Table 1

Approach to estimate the number of subjects diagnosed with advanced adenomas at the various alternative scenarios

(A) Input parameters: sensitivities for advanced adenomas at various cut-off levels according to the results of a diagnostic study that determined test performance characteristics of OC-Sensor Micro (Eiken Chemical, Tokyo, Japan).14
Cut-off level (ng haemoglobin/mL buffer)*Sensitivity for advanced adenomas (%)
≥1150
≥1447
≥2245
≥3638
≥4536
≥5035
(B) Based on these sensitivities, the number of subjects diagnosed with advanced adenomas at the various alternative scenarios was estimated in a two-step approach
Step 1 Estimating the total number of subjects with advanced adenomas in the cohort at baseline:
Given a sensitivity of 35% for advanced adenomas at a cut-off level of ≥50 ng/mL, those subjects diagnosed with advanced adenomas in the first FIT50 round (N=126) were considered to make up for 35% of all subjects with advanced adenomas in the cohort at baseline. Dividing N=126 by 35%, it can thus be estimated that 360 subjects in the cohort had advanced adenomas at baseline.
Step 2 Estimating the number of subjects diagnosed with advanced adenomas in the hypothetical first round:
This number (N=360) was multiplied with the sensitivity for advanced adenomas at the cut-off level of each respective scenario. For example, when using a cut-off level of 22 ng/mL in the first round, it was estimated that 162 subjects would have been diagnosed with advanced adenomas (N=360 multiplied by 45%).
  • *To convert the cut-off levels into the unit ‘µg/g faeces’, the listed values need to be divided by 5 given that the test delivers 10 mg of faeces into 2 mL of buffer.

  • FIT, faecal immunochemical test for haemoglobin.