FIT screening for CRC before age 50 years associated with reduced mortality

Earlier screening for colorectal cancer (CRC) with fecal immunochemical tests (FITs) appeared effective in a recent study.

Researchers in Taiwan analyzed a community-based screening cohort to evaluate whether starting FIT screening at ages 40 to 49 years rather than age 50 years was associated with reduced CRC incidence and mortality. Patients were divided into subcohorts based on participation in early screening and regular screening (biennial FIT starting at 40 to 49 years of age) and regular screening alone (biennial FIT at ≥50 years of age). Data were collected from January 2001 to December 2019 and analyzed from January 2021 to December 2024. The study's primary outcomes were CRC incidence and mortality from CRC. The results were published June 12 by JAMA Oncology.

The study included 263,125 participants, over half of whom (55.8%) were female. Overall, 39,315 participated in early and regular screening and 223,810 participated in regular screening only. Mean follow-up was 17.4 and 17.0 years, respectively. CRC incidence (26.1 [95% CI, 22.3 to 29.9] vs. 42.6 [95% CI, 40.5 to 44.7] per 100,000 person-years) and related mortality (3.2 [95% CI, 1.9 to 4.6] vs. 7.4 [95% CI, 6.5 to 8.2] per 100,000 person-years) were both lower in the early screening group. Early screening significantly reduced CRC incidence (adjusted relative risk [aRR], 0.79; 95% CI, 0.67 to 0.94) and mortality (aRR, 0.61; 95% CI, 0.38 to 0.98) in propensity score-matched analyses. An extended nonadherence adjustment model yielded similar improvements in incidence (aRR, 0.75; 95% CI, 0.72 to 0.77) and mortality (aRR, 0.66; 95% CI, 0.62 to 0.71).

The researchers noted that age- and sex-specific cutoffs for FIT had not been established when early screening was introduced and that it's unknown whether their results are generalizable to other populations. “Initiating screening at ages 40 to 49 years, rather than waiting until age 50 years, significantly lowered CRC incidence and mortality over the long term. This was demonstrated using real-world data from a community-based early screening program that transitioned into a national screening initiative with a delayed screening design,” they wrote.

“These findings support current recommendations to lower the CRC screening initiation age.”

An accompanying editorial noted that some of the benefits of early FIT in this study may have been due to selection bias and residual confounding and that information on CRC risk factors was limited. The editorialists also pointed out that sensitivity, specificity, and positive and negative predictive values of FIT were not reported, nor were proportions of patients who had colonoscopy after a positive FIT or colonoscopy yield and complication rates.

“This analysis adds to the current limited body of literature—comprised mainly of observational studies, colonoscopy registry studies, and modeling studies—that suggests that initiating screening at an age younger than 50 years may lead to public health benefits,” the editorialists wrote. “Until randomized clinical trials are conducted and results available, observational studies such as this will be essential to inform policy and practice. Importantly, a major barrier is the proportion of people who remain unscreened, which underscores the need for improved adherence to screening protocols for individuals of all ages.”