Choice of colon capsule or colonoscopy versus default colonoscopy in FIT positive patients in the Danish screening programme: a parallel group randomised controlled trial

Background Colonoscopy is among the standard tests for colorectal cancer (CRC) screening. However, uptake varies, and alternatives such as colon capsule endoscopy (CCE) are available. The uptake and detection rate of clinically significant neoplasia with CCE, compared with colonoscopy, remain unclear in this setting. Objective The primary objective of this study was to compare the detection rates of advanced neoplasia between CCE and colonoscopy, using a pathway in which the study group could choose between the two procedures, while the control group was offered only colonoscopy. Design A randomised, intention-to-treat trial was conducted among Danish CRC screening participants who tested positive with a faecal immunochemical test (FIT). The trial compared the detection rate of advanced neoplasia (primary outcome) and the uptake rate of both approaches between the two arms. Results A total of 473 684 invitations were sent to 396 676 individuals, with 62.6% returning the test. Among them, 11 075 tests were positive (4.5%), with no significant differences between the two study groups. Among FIT-positive cases, the uptake for colonoscopy was 91.1% in the control arm and 91.7% in the study arm, where participants had a choice of methods. In the study arm, 45.8% preferred CCE, 11.4% preferred colonoscopy and 42.8% had no preference and underwent colonoscopy. Ultimately, 69.9% of patients who initially opted for CCE were later referred for colonoscopy. The rate of advanced neoplasia detection was similar between the groups: 0.67% in the study arm versus 0.64% in the control arm. Conclusion Offering CCE as an alternative to colonoscopy did not significantly alter the detection rate of advanced neoplasia, nor did it increase uptake in a screening programme with high adherence to colonoscopy following a positive FIT test. Instead, it led to a very high rate of secondary colonoscopies. Therefore, CCE cannot be recommended in this setting. Trial registration number NCT04049357 (ClinicalTrials.gov)