Colorectal cancer screening with fecal immunochemical testing or primary colonoscopy: inequities in diagnostic yield

Abstract

Background Socioeconomic inequalities in the uptake of colorectal cancer screening are well documented, but the implications on health inequity remain unclear. Methods Sixty-year-olds were randomly recruited from the Swedish population between March, 2014, and March, 2020, and invited to either fecal immunochemical testing (FIT) 2 years apart (n = 60,137) or once-only primary colonoscopy (PCOL; n = 30,400). By linkage to Statistics Sweden’s registries, we obtained socioeconomic data. In each defined socioeconomic group, we estimated the cumulative yield of advanced neoplasia (AN) in each screening arm (intention-to-screen analysis). We predicted the probability of exceeding the yield in the PCOL arm after a third round of FIT: Pr{AN_FIT3>AN_PCOL}. Results In the lowest income group, the yield of AN was 1.63% (95% confidence interval [CI] = 1.35% to 1.93%) after two rounds of FIT, in relation to 1.93% (95% CI = 1.49% to 2.40%) in the PCOL arm. We predicted Pr{AN_FIT3>AN_PCOL} = 0.86. In the highest income group, we found a more pronounced yield gap between the two screening strategies, 2.32% (95% CI = 2.15% to 2.49%) vs 3.71% (95% CI = 3.41% to 4.02%), and a very low Pr{AN_FIT3>AN_PCOL} (= 0.02). Conclusions Yields of AN from FIT 2 years apart and PCOL, respectively, were poorer, but differed lesser, in lower socioeconomic groups. The results are valuable for evaluations of health equity in organized screening for colorectal cancer. Clinical Trial Registration ClinicalTrials.gov number NCT02078804.