Systematic Review and Meta-analysis of Colon Capsule Endoscopy Accuracy for Colorectal Cancer Screening. An Alternative During the Covid-19 Pandemic?

Aim: To determine the diagnostic accuracy of colon capsule endoscopy for colorectal cancer screening.

Methods: Studies that compared the diagnostic performance of colonoscopy and second-generation colon capsule endoscopy (CCE-2) for screening of asymptomatic patients aged 50-75 years were included. The primary outcomes were sensitivity, specificity, and positive and negative likelihood ratios for polyps and adenomas measuring at least 6 mm or 10 mm.

Results: Eight full-text studies that evaluated 1602 patients were included for systematic review. Of these, 840 (52.43%) patients participated in an opportunistic screening program. The pooled outcomes of CCE-2 for polyps at least 6 mm / 10 mm were (CI = confidence interval): sensitivity: 88% (95% CI: 0.84-0.91) / 88% (95% CI: 0.82-0.93), specificity: 94% (95% CI: 0.92-0.95) / 95.5% (95% CI: 0.94-0.97); positive likelihood ratio: 11.86 (95% CI: 5.53-25.46) / 23.07 (95% CI: 6.163-86.36); negative likelihood ratio: 0.14 (95% CI: 0.1-0.21) / 0.14 (95% CI: 0.09-0.21). The area under the summary receiver operating characteristic curve for polyps at least 6 and 10 mm was 96.3% and 96.7%, respectively. The only cancer missed by complete CCE-2 was shown at multiple frames in the unblinded review. In total, 125 (7.8%) patients presented mild adverse events mostly related to bowel preparation.

Conclusion: CCE-2 is demonstrated to be an effective and safe alternative method for colorectal cancer screening. Diagnostic performance of CCE-2 for polyps of at least 6 and 10 mm was similar. Completion rates still need to be improved.