RECENT research has revealed significant regional disparities in the performance of computer-aided diagnosis (CADx) systems during colonoscopy, raising concerns about their reliability for small polyps in the proximal colon.
CADx systems are designed to assist endoscopists by differentiating between neoplastic and non-neoplastic polyps. This research specifically evaluated the impact of polyp location (proximal versus distal colon) on the diagnostic accuracy of CADx for polyps measuring ≤5 mm.
The meta-analysis included data from 11 studies, encompassing a total of 7,782 polyps. The findings demonstrated that CADx systems had significantly lower specificity in the proximal colon compared to the distal colon, which includes the rectum and sigmoid. Specificity in the proximal colon was 62%, markedly lower than the 85% observed in the distal colon, with a calculated risk ratio (RR) of 0.74 (95% CI: 0.72–0.84). Sensitivity, however, was similar between the two regions, at 89% for the proximal colon and 87% for the distal colon (RR: 1.00; 95% CI: 0.97–1.03).
Additional metrics highlighted the challenges in the proximal colon. The negative predictive value was significantly lower for proximal polyps (64%) compared to 93% for distal polyps (RR: 0.71; 95% CI: 0.64–0.79), while overall diagnostic accuracy also fell short, at 81% for proximal polyps versus 86% for distal polyps (RR: 0.95; 95% CI: 0.91–0.99). Conversely, the positive predictive value was higher in the proximal colon, at 87% compared to 76% for the distal colon (RR: 1.11; 95% CI: 1.06–1.17).
The findings emphasise the limitations of current CADx systems in diagnosing proximal polyps. While their performance in the distal colon is robust, the significantly reduced specificity and accuracy in the proximal colon suggest that these systems should not be relied upon for proximal lesions until advancements are made. Developing tailored CADx technologies will be crucial to address the unique diagnostic challenges of the proximal colon.
Ada Enesco, EMJ
Reference
Rizkala T et al. Accuracy of computer-aided diagnosis in colonoscopy varies according to polyp location: a systematic review and meta-analysis. Clin Gastroenterol Hepatol. 2024;DOI:10.1016/j.cgh.2024.08.021.
