Published online Jan 15, 2021. doi: 10.4251/wjgo.v13.i1.58
Peer-review started: October 31, 2020
First decision: November 30, 2020
Revised: December 5, 2020
Accepted: December 17, 2020
Article in press: December 17, 2020
Published online: January 15, 2021
Processing time: 67 Days and 17.5 Hours
Detecting and treating early stage colorectal cancer (CRC) and precancerous lesions is the most effective method to reduce the morbidity and mortality of CRC. Narrow-band imaging (NBI) endoscopy has been a very useful technique that has contributed to improving the detection rate of early stage CRC and precancerous lesions. Researchers have proposed a variety of NBI classifications to judge the nature of lesions accurately and select treatment strategy appropriately.
For the past few years, two new 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 originating centers by experienced endoscopists, but application in different centers among endoscopists with varying endoscopic skills remains unknown.
To achieve external validity, we evaluated the clinical application and possible problems of the NICE and JNET classifications for differential diagnosis of colorectal cancer and precancerous lesions.
Six endoscopists with varying levels of experience were divided into two groups: Highly experienced endoscopists (HEEs) and less-experienced endoscopists (LEE). 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 a randomized order using the NICE and JENT classifications separately. We calculated sensitivity, specificity, accuracy, positive and negative predictive value for each category of the two classifications.
In both the HEE and LEE groups, the specificity of JNET classification type 1 and 3 and NICE classification type 3 was > 95%, and the overall interobserver agreement was good in both groups. However, the sensitivity of JNET classification type 2B lesions for the diagnosis of high-grade dysplasia or superficial submucosal invasive carcinoma in both the HEE and LEE groups was < 55%. Compared with other types of NICE and JNET classification, the diagnostic ability of JNET type 2B was the weakest.
Due to the poor diagnostic capabilities of JNET type 2B, the type 2B lesions is still the biggest challenge for the endoscopists. So, lesions of type 2B need an additional examination to choose an appropriate treatment strategy.
The JNET type 2B lesions are the most important for curation and the most difficult to be diagnosed endoscopically, and accurate diagnosis of JNET 2B lesions still requires further efforts.