Accuracy of colon capsule endoscopy for advanced neoplasia

Second-generation colon capsule endoscopy (CCE-2) has shown promising accuracy for the diagnosis of overall neoplasia. Advanced neoplasia (AN) represents the main target of colorectal cancer screening programs. Our aim was to assess the diagnostic accuracy of CCE-2 for the detection of AN in patients with a positive result for the fecal immunochemical test (FIT) who are undergoing screening.

Patients aged 50 to 69 years with a positive result for the FIT in 4 population screening programs in Italy and Spain were enrolled. Screenees were asked to undergo CCE-2, followed by traditional colonoscopy (TC). TC was performed the same day or the following morning. Bowel preparation included a split-dose polyethylene glycol-based regimen, with sodium phosphate (NaP) with gastrografin as boosters. The CCE-2 video was read by an endoscopist blinded to the results of TC. The main outcomes were CCE-2 accuracy in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for AN when using 2 different size thresholds for TC referral (ie, polyps ≥6 mm and ≥10 mm).

Two hundred twenty-two patients were enrolled, and 178 patients completed both CCE-2 and TC (87.7%). Overall, 59 cases of AN were detected at TC. CCE-2 sensitivity was 90%, specificity was 66.1%, PPV was 57.4%, and NPV was 92.9% for AN when using a 6-mm cut-off (TC referral rate, 52.8%) and 76.7%, 90.7%, 80.7%, and 88.4% when using a 10-mm cut-off (TC referral rate, 32%), respectively. CCE-2 detected that 8 of 9 already developed colorectal cancers. Among the 41 false positives at the 6-mm cut-off, 34 (82.9%) presented with a nonadvanced adenoma at TC. Mean transit time was 4 hours and 4 minutes, and ≥70% of patients excreted the capsule within 5 hours.

In an enriched disease setting, we showed the high sensitivity of CCE-2 for the diagnosis of AN at a 6-mm cut-off. The apparently low CCE-2 specificity is related to the choice of AN as the main outcome. (Clinical trial registration number: ISRCTN 62158762.).