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Studies Examine Mailed Stool-Based Tests for Colorectal Cancer Screening in Underserved Populations

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Mailed Stool-Based CRC Screening: Two Studies Assess Effectiveness in Community Health Centers

Two separate research analyses have evaluated the effectiveness of mailed stool-based colorectal cancer (CRC) screening tests for patients in community health centers and federally qualified health centers (FQHCs). The studies focus on screening completion rates, follow-up colonoscopy rates, and equity across racial and ethnic groups.

Mailed FIT Intervention and Screening Equity

A secondary analysis of a randomized clinical trial involving 3,734 patients at two FQHC systems in North Carolina examined the effect of a mailed fecal immunochemical test (FIT) plus patient navigation for positive results on CRC screening rates.

Key Findings

The intervention increased CRC screening by 18.3 percentage points overall.

  • The effect was similar across Hispanic, non-Hispanic Black, and non-Hispanic White patients, with no statistically significant differences by race or ethnicity.
  • Among patients with a positive FIT requiring follow-up colonoscopy, the intervention's effect was also similar across racial groups.
  • However, overall colonoscopy completion rates remained substantially lower for Black patients than for White patients, even in the intervention arm.

The results were published in the journal Annals of Family Medicine. The analysis was led by Anisha P. Ganguly, MD, MPH, of UNC Health and UNC Lineberger Comprehensive Cancer Center.

Ganguly stated that the analysis shows mailed screening tests can improve screening rates for diverse populations and may help reduce CRC disparities among hard-to-reach populations.

The authors suggested that broad implementation in FQHCs among minoritized populations could improve CRC screening disparities.

Comparison of Mailed FIT vs. FIT-DNA Kits

A separate randomized study involving over 5,000 participants from eight community health centers (CHCs) in Boston and Los Angeles compared completion rates of two mailed stool-based CRC screening tests: FIT and FIT-DNA (Cologuard).

Study Design

  • Participants were adults aged 45-75 due for CRC screening.
  • 75% were Hispanic; 50% were on Medicaid.
  • Participants received either a mailed FIT with automated text reminders or a mailed FIT-DNA with manufacturer-supported outreach.
  • Patients with abnormal results received navigation support for follow-up colonoscopy.

Key Findings

After 90 days, 28% of participants who received FIT-DNA kits completed screening, compared to 23% for FIT kits with automated text reminders.

  • Time to screening was shorter in the FIT-DNA group.
  • Overall screening rates were higher in Boston than Los Angeles, but the relative advantage of FIT-DNA was greater in Los Angeles.
  • Of 1,435 screened participants, 100 had abnormal results. Follow-up colonoscopy completion within 180 days was 36% in both groups.
  • Colonoscopy completion rates were lower in Los Angeles than Boston.

The study was conducted by researchers from Mass General Brigham and UCLA Health, part of the Stand Up To Cancer Colorectal Cancer Health Equity Dream Team. Findings were published in JAMA Internal Medicine.

Researchers attributed the higher completion rate for FIT-DNA to stronger outreach support from the manufacturer and less frequent testing required (every three years versus annually for FIT).

Corresponding author Jennifer Haas stated that "CHCs are an important source of care" and that since many CHCs are under-resourced, the goal of the research was to help design an intervention to benefit people who receive care in these settings.

Haas also stated that "the best screening test will always be the one that people are able to complete."

A separate associated study at a tribal site in South Dakota also found that FIT-DNA kits increased participation in CRC screening. This finding was noted as relevant given high CRC incidence and low screening rates among Native Americans.

Background and Context

Colorectal cancer is the second most common cause of cancer death in the U.S. , with higher impact on under-resourced populations. Mailing stool-based tests to patients has been shown to increase screening rates in CHCs, but the comparative effectiveness of different tests had been unclear.

FIT-DNA tests detect blood and abnormal DNA, are repeated every three years, and include manufacturer-provided patient outreach support.

Researchers noted that differences in FIT kit performance between centers may influence abnormal result rates and should be considered when selecting kits.