Aims:
Paris Classification is used to classify gastrointestinal superficial neoplastic lesions and also to estimate submucosal invasion. We aimed to evaluate the interobserver agreement for this classification among westerns endoscopists.
Methods:
A total of 54 superficial gastric lesions were independently classified according to Paris classification by 8 endoscopists. Observers were asked to classify 2 sets of images – first, obtained with high resolution white light (HR-WL) endoscopy and second, with the same HR-WL images paired with images obtained with high resolution Narrow Band Imaging (HR-NBI) – HR-WL+ NBI image group.
Results:
The overall interobserver agreement when asked to classify in I, II or III was good both using HR-WL images and HR-WL + NBI images (wK of 0.65 and 0.70, respectively). The proportion of agreement for type III lesions was 0.48 for HR-WL images increasing significantly to 0.74 in the HR-WL+NBI group. The interobserver agreement for the identification of a IIc component was only moderate (wK 0,47) and did not improve with HR-NBI namely for experts and beginners, whereas it increased for trainees (from 0.19 to 0.47). The observers had higher specificity than sensitivity in predicting submucosal invasion and with HR-NBI images the sensitivity improved among the less experienced endoscopists.
Conclusions:
Overall, the reliability of Paris classification is moderate to good. Both training and the use of technology such as NBI may improve both reliability and accuracy.
