Table 2

Positivity rate, number of subjects diagnosed with advanced adenomas, number of screen-detected CRCs, number of early stage CRCs and number of FITs and colonoscopies for the standard scenario and the respective estimates for various alternative scenarios

CRCs (overall: n=36) FITs and colonoscopies, n
Early stage CRCs (UICC I or II), n  
Positivity rateSubjects with advanced adenomas*, nScreen-detected CRCs†, nDefinitePossibly, category A‡Possibly, category B‡FITsColonoscopies
Standard scenario
13% (580/4523)1802826NANA7950580
Alternative scenarios
Cut-off level (ng haemoglobin/mL buffer)§
≥1118% (826/4523)1802722324523826
≥1416% (745/4523)1692722324523745
≥2213% (578/4523)1622622224523578
≥3610% (460/4523)1372321134523460
≥459% (410/4523)1282221034523410
≥508% (380/4523)1262221034523380
  • *For the hypothetical scenarios, the numbers of subjects with advanced adenomas were estimated as described in table 1.

  • †The number of interval CRCs was calculated by subtracting the number of screen-detected CRCs from the overall number of CRCs (n=36).

  • ‡As described in more detail in the online supplementary material, these categories take into account that there is uncertainty regarding stage progression for some CRCs in the alternative scenarios. Category A: CRCs diagnosed at an advanced stage during the follow-up period that might have been at an early (or precancerous) stage if detected at baseline. Category B: this category refers to CRCs that were detected at an early stage in the second FIT50 round (ie, the round that was skipped at the alternative scenarios) and had a haemoglobin level in the first round below the cut-off level of the respective alternative screening scenario. As justified in the online supplementary material, we considered half of these CRCs to be possibly still at an early stage if diagnosed later.

  • §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.

  • CRC, colorectal cancer; FIT, faecal immunochemical test for haemoglobin.