To optimize FIT-based screening programs, we investigated the association between fecal hemoglobin (fHb) concentrations below the FIT cut-off value and later development of colorectal advanced neoplasia (AN).
In conclusion, the age of 58 years old was the best-fit cut-off for our purposes, and when used in the newly proposed ASR, the diagnostic abilities are the same as when either 40 or 58 years old is chosen as a cut-off.
Colonoscopy was offered to screenees with a positive gFOBT or FIT (cut-off 50 ng haemoglobin/ml).
Stratified analyses and the multivariate analysis were performed for a FIT cut-off value of 50, 75 and 100 ng/ml.
The FIT cut-off level varied between 50 and 200 ng haemoglobin/ml, and the screening schedule was varied with respect to age range and interval.
At the same time, increasing the FIT cut-off from 50 to 75 ng ml−1 had a considerably stronger limiting effect on the proportion of FIT positives (falling from 8.1 to 5.7%) than any other similar further increase of the FIT cut-off (Table 1).
Within an exemplary screening strategy, biennial FIT from the age of 55 75 years, one-sample FIT provided 76.0 97.0 life-years gained (LYG) per 1000 individuals, at a cost of €259 000 264 000 (range reflects different FIT cut-off levels).
The strategy of biennial one-sample FIT screening from age 55 to 75 years yielded 76.0 97.0 LYG per 1000 individuals aged 45 years and older, compared with no screening (the range in LYG reflects different FIT cut-off levels).
We found that the NNscope was higher with FIT than with gFOBT screening when using an FIT cut-off of 50 ng ml−1, but this changed in favour of FIT when increasing the cut-off to 75 ng ml−1 (Table 1).
We believe that simulating the range of varying strategies is one of the strengths of this analysis, because we were primarily interested in the comparison of different FIT screening strategies with varying numbers of samples provided, FIT cut-off levels, screening intervals and age ranges.
Of course, this is only one of a range of possible implementation options; others might include rollout area by area or across age groups until the full country/age range is incorporated or setting a high FIT cut-off level for colonoscopy referral.
