Diagnostic performance of narrow-band imaging international colorectal endoscopic and Japanese narrow-band imaging expert team classification systems for colorectal cancer and precancerous lesions

BACKGROUND In recent years,two new narrow-band imaging(NBI)classifications have been proposed:The NBI international colorectal endoscopic(NICE)classification and Japanese NBI expert team(JNET)classification.Most validation studies of the two new NBI classifications were conducted in classification setting units by experienced endoscopists,and the application of use in different centers among endoscopists with different endoscopy skills remains unknown.AIM To evaluate clinical application and possible problems of NICE and JNET classification for the differential diagnosis of colorectal cancer and precancerous lesions.METHODS Six endoscopists with varying levels of experience participated in this study.Eighty-seven consecutive patients with a total of 125 lesions were photographed during non-magnifying conventional white-light colonoscopy,non-magnifying NBI,and magnifying NBI.The three groups of endoscopic pictures of each lesion were evaluated by the six endoscopists in randomized order using the NICE and JENT classifications separately.Then we calculated the six endoscopists’sensitivity,specificity,accuracy,positive predictive value,and negative predictive value for each category of the two classifications.RESULTS The sensitivity,specificity,and accuracy of JNET classification type 1 and 3 were similar to NICE classification type 1 and 3 in both the highly experienced endoscopist(HEE)and less-experienced endoscopist(LEE)groups.The specificity of JNET classification type 1 and 3 and NICE classification type 3 in both the HEE and LEE groups was>95%,and the overall interobserver agreement was good in both groups.The sensitivity of NICE classification type 3 lesions for diagnosis of SM-d carcinoma in the HEE group was significantly superior to that in the LEE group(91.7%vs 83.3%;P=0.042).The sensitivity of JNET classification type 2B lesions for the diagnosis of high-grade dysplasia or superficial submucosal invasive carcinoma in the HEE and LEE groups was 53.8%and 51.3%,respectively.Compared with other types of JNET classification,the diagnostic ability of type 2B was the weakest.CONCLUSION The treatment strategy of the two classification type 1 and 3 lesions can be based on the results of endoscopic examination.JNET type 2B lesions need further examination.

Diagnostic value of novel retroflexion colonoscopy in the right colon: A randomized controlled trial

BACKGROUND Colonoscopy is the accepted gold standard for the detection of colorectal cancer. However, colonoscopy is less effective in preventing colon cancer in the right side compared with the left side.AIM To investigate the feasibility of a novel type of retroflexion colonoscope, EC-3490 Ti colonoscope, for detection of proximal colon lesions.METHODS In this prospective trial, we recruited patients who underwent colonoscopy for screening or surveillance. When the endoscopists could not grasp the whole observation of the right-side colon mucosa in the forward view(FV), insertion and withdrawal were repeatedly performed in the FV group with the EC38-i10 F colonoscope while retroflexion was performed in the retroflexed view(RV) group with the EC-3490 Ti colonoscope. Adenoma detection rate, the total number of adenomas per positive participant, the success rate of retroflexion, and endoscope withdrawal time were recorded and compared.RESULTS The total adenoma detection rate(39.3% vs 37.7%, P = 0.646) did not show any significant difference between the two groups. However, the polyp detection rate(59.6% vs 51.0%, P = 0.002), adenoma detection rate in the right colon(21.6% vs 14.4%, P = 0.012), and the total number of adenomas per positive participant(2.1 vs 1.7, P = 0.011) reached statistical significance. Retroflexion was achieved in 91.7% of our cohort. Compared with the FV group, the withdrawal time was significantly prolonged in the RV group(586.1 ± 124.4 s vs 508.8 ± 129.6 s, P < 0.001). In contrast, the proportion of additional ancillary pressure decreased(27.4% vs 45.7%, P < 0.001), and the visual analog scale pain scores did not increase(2.7 ± 1.4 vs 2.8 ± 1.4, P = 0.377).CONCLUSION Retroflexion in the proximal colon could be performed successfully and safely with the EC-3490 Ti colonoscope. This maneuver could detect more adenomas effectively.