Fecal Immunochemical Test Screening Effective at 4 Years

Ricki Lewis, PhD

January 26, 2016

The fecal immunochemical test (FIT) is highly effective for annual colorectal cancer screening programs for average-risk patients, according to results of a study published online January 26 in the Annals of Internal Medicine.

FIT offers several advantages over guaiac-based fecal occult blood tests for colorectal cancer (CRC) and has a sensitivity of 79% for a single use, but its utility has not been evaluated for repeated screenings over time.

FIT is more appealing to patients because fecal occult blood testing requires dietary and medication restrictions, and FIT does not. FIT also has a higher detection rate for advanced adenomas and CRC than fecal occult blood testing.

Christopher D. Jensen, PhD, MPH, from Kaiser Permanente Division of Research, Oakland, California, and colleagues conducted a retrospective cohort study of use of FIT in annual CRC screening among 323,349 Kaiser Permanente Northern and Southern California health plan members aged 50 to 70 years, for a median of 4 years beginning in 2007 or 2008. The initial kit was mailed to 670,841 health plan members, for a return rate of 48.2%.

Outcomes were screening participation, positive FIT (≥20 μg hemoglobin/g), positive predictive values for adenoma and CRC, and sensitivity of FIT in detecting CRC.

Participation of patients who remained eligible after the first screen was 75.3%, 83.4%, and 86.1% for rounds 2, 3, and 4, respectively. After four screening rounds, 32% of the participants had endoscopy instead of FIT, with 7.0% of them doing so after a positive FIT result.

FIT positivity rate (5.0%) and positive predictive values (adenoma, 51.5%; CRC, 3.4%) were highest in round 1. FIT screening detected 80.4% of patients with CRC diagnosed within 1 year of testing, including 84.5% in round 1 and 73.4% to 78.0% in subsequent rounds.

"These findings suggest high FIT sensitivity for CRC over several rounds of testing, inform colonoscopy quality metrics for adenoma detection in patients with positive FIT results, and indicate that annual programmatic FIT screening is both feasible and effective for CRC screening in a large community-based setting," the researchers conclude.

Limitations of the investigation include possible nonextension of findings to other populations, lack of comparison to other screening methods, not accounting for patients who left the health plan, and not assessing the effect of long-term cancer prevention from polyp removal.

The study was conducted through the National Cancer Institute–funded Population-based Research Optimizing Screening through Personalized Regimens. One author reports being a one-time consultant for Exact Sciences. The Remaining authors have disclosed no relevant financial relationships.

Ann Intern Med. Published online January 26, 2015. Abstract


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