Colorectal cancer screening outreach is a vital strategy for reducing cancer mortality, especially among underresourced populations. Consequently, researchers conducted the CARES pragmatic cluster randomized clinical trial to determine the best method for increasing screening uptake. The study compared two different mailed testing approaches within community health centers to identify which strategy yielded better patient participation.

Comparing FIT and FIT-DNA Mailed Strategies

Specifically, the trial enrolled over 5,100 eligible adults aged 45 to 75 across community health centers in Boston and Los Angeles. One group received a mailed fecal immunochemical test (FIT) accompanied by automated text message reminders. In contrast, the second group received a mailed FIT-DNA kit which included the manufacturer's own outreach protocol. Furthermore, the results showed that at 90 days, screening participation was significantly higher in the FIT-DNA group at 27.9%, compared to 22.6% in the FIT group. This trend persisted through the 180-day follow-up period, suggesting that the more intensive outreach associated with FIT-DNA may improve initial engagement.

Improving Results with Colorectal Cancer Screening Outreach

Moreover, the study highlighted significant geographical differences in screening success. For example, participants in Boston health centers demonstrated higher participation rates than those in Los Angeles. However, a major concern emerged regarding follow-up care for patients with abnormal results. Specifically, only 36% of individuals with an abnormal stool test completed a follow-up colonoscopy within six months. This suboptimal rate occurred despite the availability of navigation services designed to help patients through the diagnostic process. Therefore, while colorectal cancer screening outreach effectively boosts initial test completion, healthcare systems must still address the barriers preventing definitive diagnostic follow-up.

Clinical Practice Implications

In addition to participation rates, the study suggests that the choice of screening modality should consider the level of outreach support provided. FIT-DNA programs often include integrated patient assistance, which can alleviate the administrative burden on community health centers. Nevertheless, clinicians must prioritize ensuring that every positive stool-based test is followed by a timely colonoscopy to prevent advanced disease. Improving this transition remains a critical challenge for primary care and gastroenterology teams alike.

Frequently Asked Questions

Why is mailed outreach used for colorectal cancer screening?

Mailed outreach helps overcome logistical barriers such as transportation and scheduling. By delivering tests directly to the patient's home, healthcare providers can reach underserved individuals who may not visit a clinic regularly for preventive care.

Which is more effective: FIT or FIT-DNA?

The CARES trial found that FIT-DNA resulted in higher screening participation rates. However, both tests are valid screening options, and the most important factor is the successful completion of a follow-up colonoscopy if the initial stool test returns an abnormal result.

What were the main barriers to follow-up in the CARES trial?

Despite the use of patient navigation, only 36% of patients with abnormal results completed a colonoscopy. Barriers likely include limited access to specialized care, insurance issues, and patient-level factors that require more intensive support beyond simple outreach.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or establish a doctor-patient relationship. Always seek the advice of a qualified healthcare provider regarding any medical condition. Refer to the latest local and national guidelines for clinical practice.

References

May FP et al. Mailed Outreach for Colorectal Cancer Screening in Community Health Centers: The CARES Pragmatic Cluster Randomized Clinical Trial. JAMA Intern Med. 2026 Apr 27. doi: 10.1001/jamainternmed.2026.1170. PMID: 42043827.

Imperiale TF, et al. Next-Generation Multitarget Stool DNA Testing for Colorectal-Cancer Screening. N Engl J Med. 2024;390(13):1159-1168.

USPSTF. Screening for Colorectal Cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;325(19):1965–1977.