Study Finds Fecal Immunochemical Test Effective for Annual Colon Cancer Screening
Although the fecal immunochemical test is a common method for colorectal cancer screening, its acceptability and performance over several rounds of annual testing are largely unknown. Now, a large retrospective cohort study by Jensen et al assessing the fecal immunochemical test performance characteristics over four rounds of annual screening has found that the test was associated with high sensitivity for colorectal cancer, with high adherence to annual follow-up screening among initial participants. The findings, according to the study, indicate that annual fecal immunochemical test screening is feasible and effective for population-level colorectal cancer screening. The study was published in the Annals of Internal Medicine.
Study Methodology
The retrospective longitudinal study was performed in a fixed cohort of Kaiser Permanente Northern California (KPNC) and Southern California (KPSC) health plan members. A total of 670,841 patients, aged 50 to 70 years, meeting the study eligibility criteria were mailed a fecal immunochemical test kit in 2007 or 2008, and 323,349 (48.2%) completed the test within 1 year of the mail date and were followed for up to four screening rounds.
Performance measures were stratified by sex, age, and region and included fecal immunochemical test positivity (≥ 20 μg of hemoglobin/g), positive predictive values for adenoma and colorectal cancer, and fecal immunochemical test sensitivity for detecting colorectal cancer obtained from Kaiser Permanente electronic databases and cancer registries.
Study Findings
Of the patients invited for screening, 48.2% participated in round 1. Of those who remained eligible, 75.3% to 86.1% participated in subsequent rounds. Median follow-up was 4.0 years, and 32% of round 1 participants crossed over to endoscopy over 4 screening rounds—7.0% due to a positive fecal immunochemical test result. The fecal immunochemical test positivity rate (5.0%) and positive predictive values (adenoma, 51.5%; colorectal cancer, 3.4%) were highest in round 1. Overall, programmatic fecal immunochemical test screening detected 80.4% of patients with colorectal cancer diagnosed within 1 year of testing, including 84.5% in round 1 and 73.4% to 78.0% in subsequent rounds.
The limitation of the study, noted the researchers, was that screening detection was evaluated rather than long-term cancer prevention.
“Annual fecal immunochemical test screening was associated with high sensitivity for colorectal cancer, with high adherence to annual follow-up screening among initial participants. The findings indicate that annual programmatic fecal immunochemical test screening is feasible and effective for population-level colorectal cancer screening,” concluded the study researchers.
Douglas A. Corley, MD, PhD, of Kaiser Permanente, is the corresponding author for this study.
Funding for this study was provided by the National Cancer Institute (NCI). Drs. Jensen, Corley, Quesenberry, and Levin reported grant support from the NCI during the conduct of the study. Dr. Quinn reported grant support from the National Institutes of Health during the conduct of the study. Dr. Doubeni reports compensation for one-time consultancy (Exact Sciences) outside the submitted work.
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