Kee Wook Jung

Narrow-band imaging and white-light endoscopy with optical magnification in the diagnosis of dysplasia in Barrett’s esophagus: results of the Asia-Pacific Barrett’s Consortium

Objective: The advent and utility of new endoscopic imaging modalities for predicting the histology of Barrett’s esophagus (BE) in real time with high accuracy appear promising and could potentially obviate the need to perform random biopsies where guidelines are poorly adhered to. We embarked on evaluating the performance characteristics of white-light endoscopy with magnification (WLE-z), narrow-band imaging with magnification (NBI-z) and a combination of both modalities. Design: This was a prospective online study with 28 endoscopists from 11 countries (Asia-Pacific region) participating as assessors. In total, 35 patients with BE were assessed using 150 slides from WLE-z and NBI-z randomly arranged using a simple classification with corresponding histology. The overall Accuracy (Acc), Sensitivity (Sn), Specificity (Sp), Positive Predictive Value (PPV), and Negative Predictive Value (NPV) of WLE-z, NBI-z and a combination of both were calculated. Results: The overall Acc for WLE-z and NBI-z images was 87.1u200a% and 88.7u200a%, respectively. When images from the two modalities were placed side by side, the Acc increased to 90.3u200a%. The Sn, Sp, PPV, and NPV of WLE-z were 48u200a%, 92u200a%, 45u200a%, and 93u200a% while with NBI-z, these improved to 89u200a%, 89u200a%, 56u200a%, and 98u200a%, respectively. When both imaging modalities were viewed together, they improved further to 93u200a%, 90u200a%, 61u200a%, and 99u200a%. Conclusion: The high NPV (99u200a%) when both WLE-z and NBI-z were used simultaneously indicates that areas with regular appearance that are diagnosed with confidence can effectively be left alone and not biopsied when performed at a skilled resourced center. This approach could potentially lead to a paradigm shift of how patients with BE are assessed.

The effect of eradication of Helicobacter pylori on gastric cancer prevention in healthy asymptomatic populations

Although many epidemiologic studies have evaluated the effect of Helicobacter pylori eradication on gastric cancer, the effect is still uncertain in general populations. We evaluated whether H. pylori eradication would affect the incidence of gastric cancer in healthy asymptomatic populations.

The incidence and locational predilection of metachronous tumors after endoscopic resection of high-grade dysplasia and early gastric cancer.

BackgroundThe incidence of metachronous lesions after endoscopic resection (ER) of high-grade dysplasia (HGD) has not been evaluated, and optimal surveillance strategy remains vague. This study aimed to evaluate the incidence and characteristics of metachronous tumors including HGD and early gastric cancer (EGC) arising after ER.PatientsThe medical records of 2779 patients with 2981 lesions (445 patients with HGD and 2334 patients with EGC) who underwent ER and surveillance endoscopy at Asan Medical Center between April 1999 and December 2011 were retrospectively reviewed, and clinicopathological features of metachronous tumors were analyzed.ResultsNinety-six metachronous lesions (17 HGD and 79 EGC) occurred in 92 patients during median 42xa0months of follow-up period (range 26–58xa0months). The 5-year and 10-year overall cumulative incidences of metachronous tumors were 4.6 and 10.5xa0%, respectively, and were on steady rise up to 10xa0years. The 5- and 10-year cumulative incidences of metachronous lesions were 4.1 and 8.4xa0% in HGD group and 4.7 and 11.3xa0% in EGC group (Pxa0=xa00.578), respectively. The size of metachronous tumors was significantly smaller than initial lesion (2.3 vs. 1.9xa0cm, Pxa0=xa00.039). Lower third of the stomach was most frequent site for both initial and metachronous lesions (77.1 and 70.8xa0%, respectively) and age was the significant predicting factor for metachronous tumors.ConclusionsCumulative incidence of metachronous tumors after ER of HGD was comparable to the incidence after ER of EGC. Surveillance endoscopy can be considered at least for 10xa0years, with special attention on the lower third of the stomach.