Second-generation colon capsule endoscopy compared with colonoscopy

Colon capsule endoscopy (CCE) represents a noninvasive technology that allows visualization of the colon without requiring sedation and air insufflation. A second-generation colon capsule endoscopy system (PillCam Colon 2) (CCE-2) was developed to increase sensitivity for colorectal polyp detection compared with the first-generation system. OBJECTIVE: To assess the feasibility, accuracy, and safety of CCE-2 in a head-to-head comparison with colonoscopy. DESIGN AND SETTING: Prospective, multicenter trial including 8 European sites. PATIENTS: This study involved 117 patients (mean age 60 years). Data from 109 patients were analyzed. INTERVENTION: CCE-2 was prospectively compared with conventional colonoscopy as the criterion standard for the detection of colorectal polyps that are >/=6 mm or masses in a cohort of patients at average or increased risk of colorectal neoplasia. Colonoscopy was independently performed within 10 hours after capsule ingestion or on the next day. MAIN OUTCOME MEASUREMENTS: CCE-2 sensitivity and specificity for detecting patients with polyps >/=6 mm and >/=10 mm were assessed. Capsule-positive but colonoscopy-negative cases were counted as false positive. Capsule excretion rate, level of bowel preparation, and rate of adverse events also were assessed. RESULTS: Per-patient CCE-2 sensitivity for polyps >/=6 mm and >/=10 mm was 84% and 88%, with specificities of 64% and 95%, respectively. All 3 invasive carcinomas were detected by CCE-2. The capsule excretion rate was 88% within 10 hours. Overall colon cleanliness for CCE-2 was adequate in 81% of patients. LIMITATIONS: Not unblinding the CCE-2 results at colonoscopy; heterogenous patient population; nonconsecutive patients. CONCLUSION: In this European, multicenter study, CCE-2 appeared to have a high sensitivity for the detection of clinically relevant polypoid lesions, and it might be considered an adequate tool for colorectal imaging

Response

We would like to thank Dr Balderramo for his interest in our study, and we thank the editors for an opportunity to preview and respond to his letter. Dr Balderramo brings up several important points and questions, which we can respond to. The first question raised relates to the isolated accuracy of probe-based confocal laser endomicroscopy (pCLE) compared with the accuracy of tissue sampling. Previous studies have examined the \u201cisolated\u201d performance of pCLE to diagnose cholangiocarcinoma by consensus and individual review of edited images in a blinded fashion.1 and 2 In this study, we recognized that the treating physician is never unbiased when performing pCLE, having met and examined the patient and reviewed all previous studies. We therefore chose to study the clinical impression of the physician at the time of pCLE and after tissue sampling returned because these are the metrics that drive decision making. Thus, the performance of pCLE alone cannot be determined in this study design because it cannot be isolated from the clinical impression of the treating physician at the time of pCLE, as we have done in prior studies. We apologize for any confusion generated by Table 3 in our article, where the last column shows the performance of ERCP plus tissue sampling of the blinded reviewer (second investigator), who had access only to single images of ERCP, CT, and a brief clinical vignette along with the tissue sampling results. Dr Balderramo asks for the clinical ERCP impression of the second investigator, which we had chosen not to present. This blinded investigator\u2019s impression of ERCP underperformed compared with the primary investigator, with accuracy, sensitivity, and specificity of 69%, 78%, and 53%, respectively. This is not surprising, given the limited data that were transmitted by electronic packages. We did this analysis to estimate routine clinical care without pCLE. Dr Balderramo also asked whether prior stenting of the common bile duct has an impact on the performance of pCLE. This was previously addressed in a separate study that showed slightly better performance in unstented patients.3 For the purposes of this response, we calculated the performance of ERCP plus pCLE in patients with prior stents (accuracy 80%, sensitivity 89%, specificity 71%) and in patients without prior stents (accuracy 85%, sensitivity 88%, specificity 79%) and found a nonsignificant trend toward better accuracy of pCLE in patients who had not been previously stented. Finally, we agree with Dr Balderramo that the accuracy of ERCP with pCLE should be compared with the accuracy of ERCP and tissue sampling. In our study, this could be done only by comparing data obtained from the treating physician who performed pCLE with data from the blinded second investigator, as shown in Table 3 of our article. This difference in accuracy between these 2 groups was not significant (82% for ERCP plus pCLE vs 79% for ERCP plus tissue sampling). We stand by our conclusion that the addition of pCLE to clinical impression and tissue sampling may allow for more accurate assessment of patients with indeterminate biliary strictures

Reply: To PMID 25616752

Reply: To PMID 2561675