Non-atrophic gastric mucosa is an independently associated factor for superficial non-ampullary duodenal epithelial tumors: a multicenter, matched, case-control study

Background/Aims@#The etiology of superficial non-ampullary duodenal epithelial tumors (SNADETs) remains unclear. Recent studies have reported conflicting associations between duodenal tumor development and Helicobacter pylori infection or endoscopic gastric mucosal atrophy. As such, the present study aimed to clarify the relationship between SNADETs and H. pylori infection and/or endoscopic gastric mucosal atrophy. @*Methods@#This retrospective case-control study reviewed data from 177 consecutive patients with SNADETs who underwent endoscopic or surgical resection at seven institutions in Japan over a three-year period. The prevalence of endoscopic gastric mucosal atrophy and the status of H. pylori infection were compared in 531 sex- and age-matched controls selected from screening endoscopies at two of the seven participating institutions. @*Results@#For H. pylori infection, 85 of 177 (48.0%) patients exhibited SNADETs and 112 of 531 (21.1%) control patients were non-infected (p<0.001). Non-atrophic mucosa (C0 to C1) was observed in 96 of 177 (54.2%) patients with SNADETs and 112 of 531 (21.1%) control patients (p<0.001). Conditional logistic regression analysis revealed that non-atrophic gastric mucosa was an independent risk factor for SNADETs (odds ratio, 5.10; 95% confidence interval, 2.44–8.40; p<0.001). @*Conclusions@#Non-atrophic gastric mucosa, regardless of H. pylori infection status, was a factor independently associated with SNADETs.

What Have We Accomplished in Endoscopic Image Analysis for Atrophic Gastritis?

Identifying precancerous conditions such as atrophic gastritis and intestinal metaplasia (IM) has a crucial role in detecting high risk patients for gastric cancer. White light imaging (WLI) is a basic tool for diagnosing these premalignant conditions, however its low accuracy and high variability has been a serious problem in diagnosing these premalignant conditions. Several noble imaging technologies, such as magnifying endoscopy, narrow band imaging, autofluorescence imaging, and confocal laser endomicroscopy, provids us with chances of overcoming the limitations of conventional WLI. Autofluorescence images help us understand the extent of atrophic gastritis with vivid colors. Magnifying endoscopy with narrow band imaging shows microsurface structure and micrvascular architecture and is able to identify the degree of intestinal metaplasia by the presence of "light blue crest" sign. Confocal laser endomicroscopy produces reliable images of goblet cells that can replace biopsy. Usefulness of the new endoscopic imaging techniques for predicting gastric cancer development needs to be validated in clinical practice. Currently, it would be practical to apply magnifying endoscopy with narrow band imaging sequentially after white light endoscopy for identifying the presence of IM and atrophic gastritis.

Endoscopic Diagnosis of Colorectal Neoplasms Using Autofluorescence Imaging

Many techniques have been developed to reduce the number of missed lesions during colonoscopy screening. Autofluorescence imaging (AFI) is one of the newly developed image-enhanced endoscopy (IEE) techniques, which functions similar to narrow band imaging (NBI) and flexible spectral imaging color enhancement (FICE), that can improve the detection and characterization of both polypoid and non-polypoid colonic neoplasms by enhancing their macroscopic features. We have previously reported that AFI, when used in combination with a transparent hood mounted on the tip of the endoscope to maintain distance from the colonic mucosa, results in the detection of approximately 1.6 times more colorectal neoplasms than conventional white light (WLI) colonoscopy. We have also revealed that AFI results in a higher flat neoplasm detection rate than WLI. Because the images of colorectal lesions visualized using AFI differ between histological lesion types, AFI also offers the possibility of differentiating neoplastic from non-neoplastic lesions. However, the difference between neoplastic and non-neoplastic lesions in the images generated using AFI relies on the density of the magenta coloring of the image and is therefore somewhat subjective. Recent studies suggest that NBI with magnification may be a superior modality for characterizing the neoplastic status of small colonic polyps. Although further developments are needed, the recent development of IEEs allows us to efficiently detect and differentiate colorectal neoplasms during colonoscopy screening. This article reviews the use of AFI in the diagnosis of colorectal neoplasms and discusses its advantages and limitations.