Stable prevalence of faecal immunochemical test positivity over time in Italy

The prevalence of guaiac faecal occult blood positivity among participants aged 50 in the Scottish Bowel Screening Programme showed a significant increase from 2007 to 2017. As a comparison, we examined the trend in the prevalence of faecal immunochemical test (FIT) positivity among participants aged 50 in the colorectal cancer screening programme of the Veneto region (north-east Italy) from 2006 to 2018.

The target population includes residents aged 50-69, who are invited to repeat the FIT every two years. The screening programme uses the OC-Hemodia latex agglutination test, with a cut-off for positivity of 20 µg of haemoglobin per g of faeces.

Based on 182,275 FITs performed on participants aged 50, overall FIT positivity was 3.6% in 2006 (95% confidence interval (CI): 3.1-4.2) and 3.7% (95% CI: 3.4-3.9) in 2018, showing no significant trend (p = 0.19). The prevalence of positive test results was higher in males throughout the study period. No gradient was seen for men (2006 = 4.4%, 95% CI: 3.6-5.3; 2018 = 4.2%, 95% CI: 3.9-4.6; p = 0.10) or women (2006 = 2.8%, 95% CI: 2.1-3.5; 2018 = 3.2%, 95% CI: 2.9-3.5; p = 0.84).

In a FIT-based colorectal cancer screening programme in Italy, the test positivity over time was stable. Our findings suggest that the interpretation of faecal haemoglobin levels may not be geographically transferable.