Mailed FIT Boosts CRC Screening Rates in Adults Aged 45 to 49 Years

Despite updated guidelines recommending colorectal cancer (CRC) screening start at age 45, uptake among young adults remains low.1 A new study identified that a default outreach strategy of mailing fecal immunochemical tests (FIT) directly to patients led to significantly higher screening rates than active choice approaches offering FIT, colonoscopy, or both.2

This randomized clinical trial is published in JAMA.

A randomized trial finds that default mailed outreach outperforms active choice strategies for initiating colorectal cancer screening in young adults. | Image credit: TOimages - stock.adobe.com

“This study highlights that health systems can effectively engage adults aged 45 to 49 years with mailed FIT outreach, a practice already adopted by health systems for adults aged 50 years and older,” wrote the researchers of the study.

In 2018, the American Cancer Society became the first major health organization to lower the recommended starting age for CRC screening from 50 years to 45 years for individuals at average risk.1 This change was driven by rising rates of CRC in younger adults and evidence that earlier screening offered more benefits than harms.

By 2021, additional organizations followed suit. Both the United States Preventive Services Task Force and the US Multi-Society Task Force on Colorectal Cancer updated their guidelines to recommend beginning routine screening at 45 years.

In total, 20,509 average-risk adults aged 45 to 49 years were randomly assigned in equal numbers to 1 of 4 outreach strategies aimed at promoting CRC screening.2 Participants were randomized 1:1:1:1 to receive either an active choice of FIT only, an active choice of colonoscopy only, a dual-modality active choice between FIT or colonoscopy, or usual care involving a default mailed FIT kit without requiring a choice.

The intervention period ran from May 2 to May 13, 2022, with follow-up through November 13, 2022. The primary outcome was screening completion via either FIT or colonoscopy within 6 months of outreach. The secondary outcome measured which screening modality participants completed.

Overall, 18.6% of the 20,509 participants underwent screening. Screening participation was highest in the usual care group that received a default mailed FIT kit, with 26.2% (1342 of 5126) completing screening. In contrast, participation was significantly lower in all 3 active choice groups: 16.4% (841 of 5131) in the FIT-only group, 14.5% (743 of 5127) in the colonoscopy-only group, and 17.4% (890 of 5125) in the dual-modality group.

Compared with usual care, the absolute differences in screening rates were −9.8% for FIT-only, −11.7% for colonoscopy-only, and −8.9% for dual-modality (all P < .001). Additionally, among those offered a choice between FIT or colonoscopy, colonoscopy was selected more often (12.0% vs. 5.6%).

Among those offered dual-modality active choice, colonoscopy was chosen more frequently than FIT, with 12.0% (616 of 5125) completing a colonoscopy compared with 5.6% (288 of 5125) completing a FIT (P < .001). Notably, there was substantial crossover in the FIT-only groups, with 9.8% of participants in both the FIT-only active choice and usual care default mailed FIT groups ultimately completing a colonoscopy instead. In contrast, crossover from colonoscopy to FIT in the colonoscopy-only group was relatively low, with only 2.7% (137 of 5127) completing a FIT. These findings indicate a preference for colonoscopy among participants given a choice, as well as a notable tendency for patients to switch to colonoscopy even when initially offered FIT.

However, the researcher noted some limitations. First, the study had limited generalizability, as it included only average-risk individuals with low to medium social vulnerability. Results relied on high patient portal use and a strong electronic health record system, which may not be available elsewhere. Colonoscopies done outside the system may have been missed, and the 6-month follow-up may have favored FIT due to easier access. Lastly, COVID-19 disruptions and lack of cost-effectiveness analysis were additional limitations, as was the potential difficulty of replicating the study without a waiver of consent.

Despite limitations, the researchers believe the study finds significant screening uptake with mailed FIT compared with other methods.

“This study offers robust evidence for how to engage this age group in CRC screening,” wrote the researchers. “Future research should explore further optimization and tailoring of mailed FIT outreach to enhance screening participation across diverse populations and in other health care settings.”

References

1. People ages 45-49 are not getting screened for colorectal cancer. American Cancer Society. ACS. Accessed July 30, 2025. https://www.cancer.org/research/acs-research-highlights/colon-and-rectal-cancer-research-highlights/screening---early-detection-colorectal-cancer-studies/people-45-49-not-getting-screened-for-colorectal-cancer.html

2. Galoosian A, Dai H, Croymans D, et al. Population health colorectal cancer screening strategies in adults aged 45 to 49 years. JAMA. Published online August 4, 2025. Accessed July 30, 2025. doi:10.1001/jama.2025.12049