g Hoon Youn

Signet ring cell mixed histology may show more aggressive behavior than other histologies in early gastric cancer

Signet ring cell carcinoma (SRC) of the stomach is known to have different microscopic and biologic characteristics compared to non‐SRC. The pathologic report has documented partly SRC component with main histologies. However, the clinical significance of SRC mixture has not been reported. Aim was to investigate clinicopathologic features of mixed‐SRC histology in early gastric cancer (EGC).

Development and Validation of the Korean Rome III Questionnaire for Diagnosis of Functional Gastrointestinal Disorders

Background/Aims A self-report questionnaire is frequently used to measure symptoms reliably and to distinguish patients with functional gastrointestinal disorders (FGIDs) from those with other conditions. We produced and validated a cross-cultural adaptation of the Rome III questionnaire for diagnosis of FGIDs in Korea. Methods The Korean version of the Rome III (Rome III-K) questionnaire was developed through structural translational processes. Subsequently, reliability was measured by a test-retest procedure. Convergent validity was evaluated by comparing self-reported questionnaire data with the subsequent completion of the questionnaire by the physician based on an interview and with the clinical diagnosis. Concurrent validation using the validated Korean version of the Short Form-36 Health Survey (SF-36) was adopted to demonstrate discriminant validity. Results A total of 306 subjects were studied. Test-retest reliability was good, with a median Cronbachs α value of 0.83 (range, 0.71-0.97). The degree of agreement between patient-administered and physician-administered questionnaires to diagnose FGIDs was excellent; the κ index was 0.949 for irritable bowel syndrome, 0.883 for functional dyspepsia and 0.927 for functional heartburn. The physicians clinical diagnosis of functional dyspepsia showed the most marked discrepancy with that based on the self-administered questionnaire. Almost all SF-36 domains were impaired in participants diagnosed with one of these FGIDs according to the Rome III-K. Conclusions We developed the Rome III-K questionnaire though structural translational processes, and it revealed good test-retest reliability and satisfactory construct validity. These results suggest that this instrument will be useful for clinical and research assessments in the Korean population.

Risk of electrocoagulation syndrome after endoscopic submucosal dissection in the colon and rectum

BACKGROUND AND STUDY AIMS The risk of post endoscopic submucosal dissection electrocoagulation syndrome (PEECS) is unknown. We aimed to investigate the incidence and clinicopathologic risk factors associated with PEECS after colorectal endoscopic submucosal dissection (ESD). PATIENTS AND METHODS All patients treated with colorectal ESD between 2009 and 2011 by a single expert ESD endoscopist at Gangnam Severance Hospital, Seoul, Korea were included in this retrospective study. Patients who had fever, regional rebound tenderness, or marked leukocytosis after ESD were defined as having PEECS. RESULTS 89 patients were treated during the study period. Six patients with microperforation and one patient with overt perforation were excluded. Thus, 82 cases without perforation were analyzed. The risk of PEECS was 40.2 %. In the PEECS group, the mean size of resected specimens was larger and mean procedure time was longer than in the patients without PEECS. The risk of PEECS was significantly lower for patients with carcinoid tumors, and for ESD in the rectosigmoid area. Piecemeal resection was significantly associated with the development of PEECS. In multivariate analysis, lesion size larger than 3 cm (odds ratio [OR] 5.0, 95 % confidence interval [95 %CI] 1.2 - 21.7) and site other than rectosigmoid (OR 7.6, 95 %CI 2.1 - 27.9) were independent risk factors for PEECS. CONCLUSIONS Large tumor size and tumor site other than rectosigmoid were independent risk factors related to PEECS. Patients with tumors larger than 3 cm, in colon areas other than the rectosigmoid, should be observed carefully after colorectal ESD.

Management of the complications of endoscopic submucosal dissection.

Endoscopic submucosal dissection (ESD) is currently widely accepted as a standard treatment option for early gastrointestinal neoplasms in Korea. However, ESD has technical difficulties and a longer procedure time than conventional endoscopic resection. So it may have a higher risk of complications than conventional endoscopic resection techniques. We, the ESD study group of Korean Society of Gastrointestinal Endoscopy, have experienced many complications, mostly treated by endoscopic or conservative management. Here, we introduce and share our experiences for management of post ESD complications and review published papers on the topic.

Peroral Endoscopic Myotomy for Treating Achalasia and Esophageal Motility Disorders

Peroral endoscopic myotomy (POEM) is the application of esophageal myotomy to the concept of natural orifice transluminal surgery (NOTES) by utilizing a submucosal tunneling method. Since the first case of POEM was performed for treating achalasia in Japan in 2008, this procedure is being more widely used by many skillful endosopists all over the world. Currently, POEM is a spotlighted, emerging treatment option for achalasia, and the indications for POEM are expanding to include long-standing, sigmoid shaped esophagus in achalasia, even previously failed endoscopic treatment or surgical myotomy, and other spastic esophageal motility disorders. Accumulating data about POEM demonstrate excellent short-term outcomes with minimal risk of major adverse events, and some existing long-term data show the efficacy of POEM to be long lasting. In this review article, we review the technical details and clinical outcomes of POEM, and discuss some considerations of POEM in special situations.

What is the ideal stent as initial intervention for malignant gastric outlet obstruction

BACKGROUND Self-expandable metal stents are effective palliation for malignant gastric outlet obstruction. The aims of study were to evaluate efficacy and safety of double-layered Comvi, uncovered and covered stent to find out protocols which enhance stent patency. METHODS We retrospectively analysed data from 224 patients who underwent endoscopic stent placement for malignant gastric outlet obstruction caused by stomach cancer from 2006 to 2011. Technical and clinical success rates were evaluated and clinical outcomes were compared according to stent types and chemotherapy. RESULTS The overall technical and clinical success rates were achieved in 99.6% and 80.4%, respectively without immediate complications. The clinical success rate was not significantly different between three groups. The median stent patency time was 156 days [interquartile range 66-279] without differences between groups. The 4-, 8-, and 12-week patency rates were 89.4%, 77.3%, and 61.2%, respectively with no differences between groups. The re-stenosis of stent frequently occurred in the case of the uncovered stents, while migration was more likely to be observed for the covered and Comvi stent. Chemotherapy significantly lowered re-intervention rates, especially in uncovered stents. CONCLUSIONS Patency rates are significantly improved by combining the use of uncovered stent with follow-up chemotherapy treatment, which retains the advantages of the mechanical and chemical aspects of stent and chemotherapy, respectively.

Undifferentiated early gastric cancer diagnosed as differentiated histology based on forceps biopsy

Histological diagnosis before endoscopic resection (ER) is important to determine whether ER should be performed; indeed, the use of ER for undifferentiated early gastric cancer (UD-EGC) remains controversial. The aim was to investigate the clinicopathological features of UD-EGC in ER specimens, diagnosed as differentiated histology based on biopsy. 289 patients with EGC were treated by ER. Among them, 13.1% were diagnosed as UD-EGC after ER, and 18.4% of them showed differentiated histology based on biopsy before ER. We analyzed UD-EGC with differentiated histology (D-group) compared to undifferentiated histology (UD-group) on biopsy. The D-group showed moderately differentiated adenocarcinoma on biopsy and poorly differentiated adenocarcinoma in ER specimens. The D-group was significantly associated with older age, intestinal metaplasia in the surrounding mucosa, and larger size than the UD-group. Gland portion of tumor, mixed-type Lauren classification, submucosal invasion, lymphovascular invasion, and perineural invasion were more common in the D-group than in the UD-group. The number of biopsies was not different between the groups. When comparing the histopathological mapping findings and endoscopic appearances of the D-group, the zone of transition from differentiated to undifferentiated histology was frequently found on one or two peripheral sides of the lesion. In conclusion, areas of EGC greater than 20mm with moderately differentiated histology on biopsy may contain an undifferentiated component. UD-EGC with differentiated histology on biopsy may show more aggressive behavior than UD-EGC, consistent with the biopsy pathology. Biopsy at several peripheral sides of the lesion may be helpful for diagnosis of UD histology before treatment.

Relationship between intestinal gas and the development of right colonic diverticula.

Backgrounds/Aims High intraluminal pressure has been reported to cause left colonic diverticula. However, the pathophysiology of right colonic diverticula is still unclear. Methane gas has been reported to delay small intestinal transit and to increase intraluminal pressure. The aim of this study was to evaluate the relationship between right colonic diverticula and intestinal gas produced by enteric bacteria. Methods Lactulose breath tests were performed in 30 patients who were diagnosed with right colonic diverticula via colonoscopy. The control group consisted of 30 healthy adults with no specific symptoms or medical histories. A hydrogen or methane producer was defined in 2 ways: either one that exhibited a breath hydrogen level ≥ 20 ppm (methane ≥ 10 ppm) baseline or one that exhibited an increase in breath hydrogen ≥ 20 ppm (methane ≥ 10 ppm) above baseline within the first 90 minutes of the test. Results The lactulose breath test (LBT) positivity in the diverticular group and the control group were 40.0% and 33.3%, respectively, without a statistically significant difference. The concentrations of methane and hydrogen gas measured by LBT increased over time, but there was no significant difference between the control and the diverticular groups. Conclusions There was no significant relationship between right colonic diverticula and intestinal gases produced by enteric bacteria. However, time-dependent formation of diverticula should be taken into consideration, therefore long-term, large-scale follow-up studies may reveal further pathogenesis of right colonic diverticulosis.

Factors influencing development of pain after gastric endoscopic submucosal dissection: a randomized controlled trial.

BACKGROUND AND STUDY AIMS Endoscopic submucosal dissection (ESD) is widely used for local treatment of gastric neoplasms. Although ESD-related complications such as bleeding and perforation have been reported, data are currently lacking on the development of pain, which is one of the most common adverse events after ESD. The aim of the current study was to investigate the incidence and clinicopathologic risk factors of pain after ESD. PATIENTS AND METHODS A prospective randomized controlled study was conducted to evaluate 156 patients with gastric neoplasms treated by ESD at Gangnam Severance Hospital between April 2011 and August 2013. All patients were randomly assigned to treatment with intravenous proton pump inhibitor (PPI) either before or after ESD. Acid infusion tests were performed in a subgroup of 21 patients to investigate the mechanism of pain after ESD. RESULTS The incidence of moderate-to-severe pain after ESD was significantly lower in the group that received preprocedure PPI (44.9%) compared to those who did not (62.8%). Female sex, tumors of the distal stomach (I.e. lower third), baseline dyspeptic symptoms, and positive acid infusion testing were variables that correlated significantly with the development of pain after ESD, although female sex was not significant in multivariate analysis. CONCLUSIONS Patients with tumors of the distal stomach and baseline dyspeptic symptoms were more likely to develop pain after gastric ESD. Hypersensitivity to acid was one mechanism fueling post-ESD pain. Prophylactic PPI treatment was effective at reducing post-ESD pain.Trial registered at Clinicaltrials.gov (NCT02254889).

Effects of the Addition of Mosapride to Gastroesophageal Reflux Disease Patients on Proton Pump Inhibitor: A Prospective Randomized, Double-blind Study

Background/Aims Proton pump inhibitors (PPIs) which are the most effective agents for the treatment of gastroesophageal reflux disease (GERD), have been known to delay gastric emptying. Mosapride has been used as prokinetics by accelerating gastric emptying. We evaluated the efficacy of mosapride to prevent PPI-induced delayed gastric emptying in a prospective randomized, double-blind and placebo-controlled trial. Methods Thirty patients who were diagnosed as GERD and had normal gastric emptying were included in this study. PPI monotherapy group was treated with placebo drug in addition to pantoprazole and PPI plus mosapride group was treated with mosapride in addition to pantoprazole for 8 weeks. Gastric emptying scan and questionnaires about GERD and dyspeptic symptoms were assessed by scoring before and after treatment. To evaluate the changes of gastrointestinal endocrine hormones by PPI which are associated gastric acid secretion and gastric motility, fasting plasma gastrin and cholecystokinin were taken at weeks 0 and 8. Results Half gastric emptying time was increased (P = 0.023) in PPI monotherapy group, and there were no significant changes in PPI plus mosapride group. Plasma gastrin level increased in PPI monotherpay group (P = 0.028) and there were no significant changes in PPI plus mosapride group. Plasma cholecystokinin level was not changed after treatment in both groups. GERD symptoms were improved after treatment in both groups, and postprandial bloating and nausea were improved in PPI plus mosapride group. Conclusions Mosapride showed to be effective in preventing delayed gastric emptying and the increase in plasma gastrin level induced by PPI treatment, but did not show prominent clinical symptom improvements.