Study of sensitivity of targeted biopsy and random biopsy within Sydney protocol by using narrow band imaging for extensive gastric intestinal metaplasia diagnosis
Abstract:
Background: According to the recent guideline, patients with gastric intestinal metaplasia (GIM) should have at least 5 biopsies performed under the Sydney protocol to evaluate the risk of extensive GIM. However, only narrow band imaging (NBI)-targeted biopsy may be adequate to diagnose extensive GIM. There has been no direct comparison on the performance status of these two protocols. Methods: A cross-sectional study was conducted between November 2019 and October 2020. Patients with histology proven GIM were enrolled. All patients underwent standard esophagogastroduodenoscopy (EGD) by gastroenterology trainee. The performing endoscopists took biopsy from either suspected GIM area (NBI-targeted biopsy) or randomly (if negative for GIM read by NBI) to complete 5 areas of the stomach as per the Sydney protocol. The gold standard for GIM diagnosis was the pathology read by two gastrointestinal pathologists with unanimous agreement. Results: A total of 95 patients with GIM were enrolled and 50 (52.6%) were male with mean age of 64 years. Extensive GIM was diagnosed in 43 patients (45.3%). The sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy of NBI-targeted biopsy vs. the Sydney protocol were 88.4% vs.100 %, 90.3% vs. 90.3%, 88.4% vs. 89.6%, 90.3% vs. 100% and 89.5% vs. 94.7%, respectively. The number of specimens from NBI-targeted biopsy was significantly lower than that from Sydney protocol (311vs.475, p<0.001). non-NBI expert was able to optimally diagnose GIM by using NBI-targeted biopsy alone, achieved sensitivity of 100 % after performing EGD in 60 GIM cases. Conclusion: NBI-targeted biopsy by non-NBI expert gastroenterologist provided sensitivity lesser than Sydney protocol. however after performing EGD in 60 GIM cases NBI targeted biopsy alone achieved sensitivity of 100 % as same as Sydney protocol. Thus, targeted biopsy that requires less number of specimens is adequate for extensive GIM diagnosis.