The UK nationwide observational study of colon capsule: CAP ACCESS study

Abstract

Background: Colon capsule endoscopy (CCE) is increasingly used as an alternative to optical endoscopy (OE), particularly in Europe. However, challenges like low completion rates, inadequate bowel preparation, high conversion to OE, and discrepancies in findings remain. Accurate polyp size measurement in CCE is essential to avoid unnecessary procedures due to size overestimation.

Objective(s): This retrospective study analysed real-world data to compare polyp size measurements between CCE, OE, and histopathology (HP) and assess the impact on the need for further procedures.

Methods: Data from 2508 participants across 12 UK centres were analysed, with 4898 polyps identified via CCE. Polyps were matched with OE and HP reports based on size, location, morphology, sequence, and count, including those meeting ≥3 criteria. Regional data from Scotland and England were compared.

Results: Half of the CCE patients required follow-up OE, with 29 % undergoing colonoscopy. Among these, 32 % required OE for polypectomy, and 18 % due to incomplete CCE. In these cases, CCE overestimated polyp size by an average of 2.5 mm compared to HP and 2.7 mm compared to OE, leading to 17.3 % of potentially deferrable procedures.

Conclusion: one in six participants had a further procedure reflecting the overestimation of polyp size. AI advancement could enhance polyp measurement accuracy and reduce unnecessary procedures whilst improving the cost-effectiveness of CCE.

Keywords: Bowel preparation; Capsule endoscopy; Colon capsule endoscopy; Colonoscopy; Completion rate; Histopathology; Panenteric capsule endoscopy.