FIT Screening Outcomes Stabilize After Initial Round but Remain Clinically Relevant Over Time

Long-term data from an organized biennial fecal immunochemical test (FIT)–based colorectal cancer (CRC) screening program show that detection rates decline after the first round but remain clinically meaningful across multiple screening cycles.

Investigators analyzed 2.81 million individuals invited to participate in up to seven screening rounds between 2010 and 2023. Adherence was categorized by proportion of completed rounds, with 29.2% completing all offered rounds and 46.2% never participating. Outcomes were assessed in the full invitee population and in an adherent cohort entering screening at ages 50 to 51.

Across both groups, the first screening round produced the highest FIT positivity rates, positive predictive values (PPVs) for CRC and high-risk precursor lesions, and CRC detection per 1000 participants. In the full invitee population, first-round FIT positivity was 5.8%, with a CRC PPV of 5.1% and a detection rate of 2.65 per 1000 participants. Similar trends were observed in the adherent cohort.

After three rounds, screening outcomes stabilized at lower levels. For example, CRC PPV in the seventh round ranged from 1.6% to 2.2% at median ages 62 to 65, compared with 6.6% among first-time screeners of similar age. These findings likely reflect removal of prevalent neoplasia in earlier rounds and selection of a lower-risk population over time.

Colonoscopy completion after a positive FIT remained high at 87.3%, reinforcing the program’s effectiveness in ensuring diagnostic follow-up.

The authors concluded that “after an initial round with the highest FIT-positivity and detection rates, screening outcomes stabilise at lower levels reflecting neoplasia removal.” They further emphasized that “early screening cessation after a sequence of normal biennial FITs is not justified.”

Reference
Ladabaum U, Font Marimon R, Castells X, et al. Effect of long-term adherence on faecal immunochemical test positivity rate, positive predictive value and detection rate in organised population-based colorectal cancer screening. Gut. Published online February 9, 2026. doi:10.1136/gutjnl-2025-336994