Yong Hwan Kwon

Long-term follow up of endoscopic resection for type 3 gastric NET

AIM To clarify the short and long-term results and to prove the usefulness of endoscopic resection in type 3 gastric neuroendocrine tumors (NETs). METHODS Of the 119 type 3 gastric NETs diagnosed from January 1996 to September 2011, 50 patients treated with endoscopic resection were enrolled in this study. For endoscopic resection, endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) was used. Therapeutic efficacy, complications, and follow-up results were evaluated retrospectively. RESULTS EMR was performed in 41 cases and ESD in 9 cases. Pathologically complete resection was performed in 40 cases (80.0%) and incomplete resection specimens were observed in 10 cases (7 vs 3 patients in the EMR vs ESD group, P = 0.249). Upon analysis of the incomplete resection group, lateral or vertical margin invasion was found in six cases (14.6%) in the EMR group and in one case in the ESD group (11.1%). Lymphovascular invasions were observed in two cases (22.2%) in the ESD group and in one case (2.4%) in the EMR group (P = 0.080). During the follow-up period (43.73; 13-60 mo), there was no evidence of tumor recurrence in either the pathologically complete resection group or the incomplete resection group. No recurrence was reported during follow-up. In addition, no mortality was reported in either the complete resection group or the incomplete resection group for the duration of the follow-up period. CONCLUSION Less than 2 cm sized confined submucosal layer type 3 gastric NET with no evidence of lymphovascular invasion, endoscopic treatment could be considered at initial treatment.

Predictive Factors for Lymph Node Metastasis in Signet Ring Cell Gastric Cancer and the Feasibility of Endoscopic Submucosal Dissection

Purpose Endoscopic submucosal dissection has recently been practiced on a differentiated type of early gastric cancer. However, there is no clear evidence for endoscopic treatments of signet ring cell carcinoma. The aim of this study is to identify the predictive clinicopathological factors for lymph node metastasis in signet ring cell carcinoma for assisting endoscopic submucosal dissection trials. Materials and Methods A total of 186 patients with early signet ring cell carcinoma who underwent radical curative gastrectomy between January 2001 and September 2009 were enrolled in this study. Retrospective reviews of their medical records are being conducted. Several clinicopathologic factors were being investigated in order to identify predictive factors for lymph nodes metastasis: age, gender, tumor size, type of operation, tumor location, gross type, ulceration, Laurens classification, depth of invasion, and lymphatic invasion. Results The lymph node metastasis rate for signet ring cell carcinoma was 4.3% (n=8). Of the 186 lesions with early signet ring cell carcinoma, 91 (48.9%) tumors were larger than 15 mm in size and 40 (21.5%) showed submucosal invasions in the resection specimens. In multivariate analysis, only the lymphatic invasion (P<0.0001) showed an association with lymph node metastasis. To evaluate cutoff values for tumor sizes in the presence of lymph node metastasis, early signet ring cell carcinomas with lymphatic invasions were excluded. In the absence of lymphatic invasion, mucosal cancer with tumor sizes <15 mm had no lymph node metastasis. Conclusions Endoscopic submucosal dissection can be performed on patients with early signet ring cell carcinoma limited to the mucosa and less than 15 mm.

Endoscopic Management of Refractory Benign Colorectal Strictures

In colonoscopic study, benign colorectal strictures with or without symptomatic pain are not rarely encountered. Benign colorectal stricture can be caused by a number of problems, such as anastomotic stricture after surgery, inflammatory bowel disease, postendoscopic submucosal dissection, diverticular disease, ischemic colitis, and so on. There are various modalities for the management of benign colorectal stricture. Endoscopic balloon dilatation is generally considered as the primary treatment for benign colorectal stricture. In refractory benign colorectal strictures, several treatment sessions of balloon dilatation are needed for successful dilatation. The self-expandable metal stent and many combined techniques are performed at present. However, there is no specific algorithmic modality for refractory benign colorectal strictures.

Endoscopic Management of Rectal Dieulafoy's Lesion: A Case Series and Optimal Treatment

Rectal Dieulafoys lesion (DL) is rare cause of lower gastrointestinal bleeding. Because of its rarity, there is no consensus on the optimal endoscopic hemostasis technique for rectal DL. We analyzed six patients who underwent endoscopic management for rectal DL after presenting with hematochezia at a single institute over 10 years. Of the six patients, three underwent endoscopic band ligation (EBL) and three underwent endoscopic hemoclip placement (EHP). Only one patient was treated with thermocoagulation. There were no immediate complications in any of the patients. None of the patients required a procedure or surgery for the treatment of rebleeding. Mean procedure times of EBL and EHP were 5.25 minutes and 7 minutes, respectively. Both EHP and EBL are shown to be effective in the treatment of bleeding rectal DL. We suggest that EBL may have potential as the preferred therapy owing to its superiority in technical and economic aspects, especially in elderly and high-risk patients.

Clinical Practice Guidelines for Irritable Bowel Syndrome in Korea, 2017 Revised Edition

In 2011, the Korean Society of Neurogastroenterology and Motility (KSNM) published clinical practice guidelines on the management of irritable bowel syndrome (IBS) based on a systematic review of the literature. The KSNM planned to update the clinical practice guidelines to support primary physicians, reduce the socioeconomic burden of IBS, and reflect advances in the pathophysiology and management of IBS. The present revised version of the guidelines is in continuity with the previous version and targets adults diagnosed with, or suspected to have, IBS. A librarian created a literature search query, and a systematic review was conducted to identify candidate guidelines. Feasible documents were verified based on predetermined inclusion and exclusion criteria. The candidate seed guidelines were fully evaluated by the Guidelines Development Committee using the Appraisal of Guidelines for Research and Evaluation II quality assessment tool. After selecting 7 seed guidelines, the committee prepared evidence summaries to generate data exaction tables. These summaries comprised the 4 main themes of this version of the guidelines: colonoscopy; a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols; probiotics; and rifaximin. To adopt the core recommendations of the guidelines, the Delphi technique (ie, a panel of experts on IBS) was used. To enhance dissemination of the clinical practice guidelines, a Korean version will be made available, and a food calendar for patients with IBS is produced.

Quality of information on the Internet for Korean patients with inflammatory bowel disease

Background/Aims The Internet is the main resource for health-related information. The incidence of inflammatory bowel disease (IBD) is rapidly increasing in Asian countries. However, the quality of websites for IBD available in this region has not been evaluated. We aimed to evaluate the quality of the information on IBD obtained from Korean websites. Methods Using the terms “Crohn’s disease” or “ulcerative colitis,” websites were selected from those obtained with the three most renowned search engines in Korea; 60 websites from the results of each engine were chosen. The websites were classified into institutional, commercial, charitable, supportive, or alternative medicine types according to the characteristics of each site. The websites were evaluated regarding content quality using the validated DISCERN instrument and the Journal of the American Medical Association benchmarks. Results The median score of all the websites according to the DISCERN instrument was 32 (interquartile range, 25 to 47) out of 80, indicating an insufficient overall quality of information. The alternative medicine sites scored the lowest, whereas the institutional sites scored the highest (p < 0.05). The quality of information was significantly different among the search engines (p = 0.028). The rank of appearance in the Google search result did not correlate with the quality level of the information. Conclusions The quality of information on the Internet regarding IBD varied according to the website type and search engine. Accreditation and quality assurance systems should be implemented for websites to ensure that the public and patients obtain accurate information on IBD.

Screening Biomarker as an Alternative to Endoscopy for the Detection of Early Gastric Cancer: The Combination of Serum Trefoil Factor Family 3 and Pepsinogen

Objective The serum pepsinogen test has limitation in its predictive power as a noninvasive biomarker for gastric cancer screening. We aimed to investigate whether the combination of TFF3 and pepsinogen could be an effective biomarker for the detection of gastric cancer even in the early stages. Methods In total, 281 patients with early gastric cancer (EGC), who underwent endoscopic submucosal dissection in Korea, and 708 healthy individuals from Japan were enrolled in the derivation cohort. The validation cohort included 30 Korean patients with EGC and 30 Korean healthy control blood donors. Serum TFF3 levels were examined using enzyme-linked immunosorbent assay. Results Using a cutoff of 6.73 ng/mL in the derivation cohort, the sensitivity of the combination of tests for EGC detection was superior (87.5%) to that of TFF3 (80.4%) or pepsinogen test alone (39.5%). Similarly, in the validation cohort, the sensitivity of TFF3 plus pepsinogen was higher (90.4%) than that of TFF3 (80.0%) or pepsinogen test alone (33.3%). Conclusion The combination of serum TFF3 and pepsinogen is a more effective noninvasive biomarker for gastric cancer detection compared with pepsinogen or TFF3 alone, even in EGC. This trial is registered with NCT03046745.

High and Frequent Dose of Dexlansoprazole and Amoxicillin Dual Therapy for Helicobacter pylori Infections: A Single Arm Prospective Study

Background/Aims Recently, the eradication rate of Helicobacter pylori (H. pylori) infection has decreased to less than 80% worldwide with the use of clarithromycin-based triple therapy owing to the increased resistance of H. pylori to antibiotics, especially clarithromycin and metronidazole. This prospective study aimed to determine eradication rate of H. pylori following high and frequent doses of extended-release dexlansoprazole and amoxicillin, as a dual therapy in a region with high clarithromycin resistance rate. Methods A total of 50 treatment-naïve patients with active H. pylori infections, who were confirmed through via rapid urease test or histology and serology between November 2015 and February 2016 at our hospital, were included for analysis. All enrolled patients were treated with 750 mg amoxicillin and 30 mg dexlansoprazole, four times a day for a total duration of 14 days. Treatment success was determined using urea breath test four weeks after treatment completion. Results Seven out of the 50 patients (29 men and 21 women; mean age, 57 years) dropped out during the study. The total eradication rate was 52% (26/50), and that for those with a compliance rate of over 90% was 68.4% (26/38). H. pylori infections were not successfully eradicated in patients with a compliance rate of less than 90%. Nine patients (18%) reported side effects, such as mild diarrhea and abdominal fullness. No significant factors, such as smoking and alcohol consumption, affected the infection the eradication rate. Conclusions High and frequent doses of proton pump inhibitor-amoxicillin dual therapy were not effective in eradicating H. pylori infection in a province with high clarithromycin resistance rate.

Long-term follow-up of pepsinogen I/II ratio after eradication of Helicobacter pylori in patients who underwent endoscopic mucosal resection for gastric cancer

BACKGROUND Although the pepsinogen I/II (PGI/II) ratio after Helicobacter pylori eradication is recovered at short-term follow-up, long-term follow-up studies of PGI/II are rare. METHODS A total of 773 patients with gastric cancer who underwent endoscopic resection and pepsinogen and H. pylori tests were enrolled. H. pylori was eradicated in these patients. Endoscopic and pepsinogen tests were performed every year. A low PGI/II ratio was defined as ≤3. RESULTS The PGI/II ratio was higher in non-infected patients (n=275, 4.99) than infected patients (n=498, 3.53). After H. pylori eradication, the PGI/II ratio increased to 5.81 and 5.63 after 1 and 2 years (each p<0.05). The PGI/II ratio in the non-eradication group decreased to 3.94 and 2.75 after 1 and 2 years. The PGI/II ratio in the H. pylori eradication group became similar to that of the H. pylori-negative group at 3 (4.48 vs. 4.34), 4 (4.88 vs. 4.34), and 5 years (4.89 vs. 4.23). The adjusted odds ratios for a lower PG I/II ratio in the non-eradication group compared to the eradication group were 4.78 (95% CI 2.15-10.67) after 1year and 8.13 (95% CI 2.56-25.83) after 2 years. CONCLUSIONS After H. pylori eradication, the PGI/II ratio increased and was similar to that of H. pylori-negative controls for up to 5 years of follow-up.

Current Status of Translational Research on Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. The pathophysiology of IBS is not completely understood. Genetic, immune, environmental, inflammatory, neurological and psychological factors contribute to the risk of this condition. Traditional research explored gastrointestinal motor abnormalities, central neural dysregulation, abnormal psychological features, and visceral hypersensitivity. More recent investigations consider bacterial overgrowth, abnormal serotonin pathways, altered gut flora, immune activation and mucosal inflammation. The purpose of this article is to review recent translational research concerning the pathophysiology, biomarker and genetic factors of IBS and to encourage IBS research in Korea.