Introduction: Screening has been shown to reduce colorectal cancer (CRC) mortality, but effectiveness of a screening program is dependent on long-term adherence. This study examined annual adherence to screening for fecal immunochemical test [FIT] and fecal occult blood test [FOBT] over a three-year period. Methods: This retrospective cohort study used IBM MarketScan administrative claims databases. Adults (age ≥45-75 years) with at least one claim for any CRC screening test (i.e. colonoscopy, FIT, FOBT, multi-target stool DNA [mt-sDNA], sigmoidoscopy, colonography, double contrast barium enema [DCBE]) during 1/1/2014-6/30/2019 were initially selected (index date = earliest CRC screening). Patients were followed continuously for three years post-index and had a look back period of 10 years pre-index. The 10-year pre-index period was used to exclude patients at high-risk for CRC and with prior CRC screening (already up to date). Patients aged >50, with a FIT or FOBT test on index, and with no claims for other screening tests during the post-index period comprised the final cohort. Year over year adherence to FIT or FOBT was measured during the three-year post-index period defined as a repeat test 12-15 months after index and a third test 12-15 months after the second test. Time to each subsequent FIT or FOBT test was also evaluated. Results: In total, 10,253 patients with FIT and 5,366 patients with FOBT were eligible for analysis. Mean age was 56.0 (FIT) and 56.3 years (FOBT), 32.8% (FIT) and 42.1% (FOBT) were male, 94.7% (FIT) and 93.0% (FOBT) were commercially insured, and the mean (standard deviation [SD]) Deyo-Charlson comorbidity score was 0.4 (0.9) ) (FIT, FOBT). The proportion adherent to repeat testing at year 2 was 23.4% (N = 2,404) for patients with FIT and 20.1% (N = 1,079) for patients with FOBT. These rates significantly (p< 0.001) declined to 10.6% (FIT, N = 1,086) and 8.5% (FOBT, N = 455) of patients who remained adherent at year 3 (Figure 1). Of patients not adherent in the second year (N = 7,849 FIT and N = 4,287 FOBT), 5.4% and 3.4% of FIT and FOBT patients were adherent in the third year. Median time from first to second test and second to third test was 12.7 months for FIT and 12.6 months for FOBT. Discussion: Results from this real-world analysis of robust claims data suggest that longitudinal adherence to annual FIT and FOBT testing is poor, substantially minimizing their potential benefits for average-risk CRC screening.
Figure 1: Proportion of Patients Adherent to FIT and FOBT Screening Guidelines
Disclosures: Deborah Fisher: Exact Sciences and Guardant Health – Consultant. Nicole Princic: IBM Watson Health – Employee. Lesley-Ann Miller-Wilson: Exact Sciences Corporation – Employee. Kathleen Wilson: IBM Watson Health – Employee. Kathryn DeYoung: IBM Watson Health – Employee. A. Burak Ozbay: Exact Sciences Corporation – Employee. Paul Limburg: Exact Sciences Corporation – Other Financial or Material Support, serves as Chief Medical Officer for Screening at Exact Sciences through a contracted services agreement with Mayo Clinic. Dr. Limburg and Mayo Clinic have contractual rights to receive royalties through this agreement..