Nomogram for pre-procedural prediction of non-curative endoscopic resection in patients with early gastric cancer.

BACKGROUND: Non-curative resection (non-CR) after endoscopic submucosal dissection (ESD) requires additional surgery due to the possibility of lymph node metastasis (LNM). Therefore, it is important to accurately predict the risk of non-CR to avoid unnecessary preoperative procedures. Thus, we aimed to develop and verify a nomogram to predict the risk of non-CR prior to ESD. METHODS: Patients who underwent ESD for early gastric cancer (EGC) were divided into CR and non-CR groups based on the present ESD criteria. The pre-procedural factors, such as endoscopic features, radiologic findings, and pathology of the lesion, were compared between the groups to identify the risk factors associated with non-CR. A nomogram was developed using multivariate analysis, and its predictive value was assessed using an external validation group. RESULTS: Among 824 patients, 682 were curative (82.7%) and 142 were non-curative (17.3%). By comparing two groups, endoscopic features including redness, whitish mucosal change, fold convergence, and large lesion size; histologic features such as moderately or poorly differentiated or signet ring cell carcinoma; and abnormal CT findings including non-specific lymph node enlargement and fold thickening were identified as significant predictors of non-CR. The nomogram was developed based on these predictors and showed good predictive performance in the external validation, with an area under the curve of 0.87. CONCLUSIONS: We developed a nomogram to predict the risk of non-CR prior to ESD. These predictive factors in addition to the existing ESD criteria can help provide the best treatment option for patients with EGC.

Effect of Drinking Warm Water on Esophageal Preparation Before Peroral Endoscopic Myotomy in Patients With Achalasia.

Background/Aims: Food retention, which is a characteristic observed in patients with achalasia, can interfere with peroral endoscopic myotomy (POEM). However, there is no established guideline for esophageal preparation for POEM. A previous study has shown that drinking warm water may reduce the lower esophageal sphincter pressure in patients with achalasia. This study aims to evaluate the possibility of proper preparation of POEM by instructing the patient to drink warm water. Methods: The warm water preparation was performed in 29 patients with achalasia who underwent POEM. The patients drank 1 L of warm water (60oC) the night before POEM. We evaluated the esophageal clearness and determined the preparation quality. Twentynine patients were prospectively recruited and compared to control group. The control cohort comprised achalasia patients whose endoscopic image was available from the achalasia database of our institution. A 1:2 propensity score-matched control cohort was established from the database of achalasia subjects (n = 155) to compare the outcome of the preparation. Results: In the warm water preparation group, only 1 patient (3.4%) had some solid retention, but it did not interfere with the POEM procedure. The grade of clearness (P = 0.016) and quality of preparation (P < 0.001) were significantly better in the warm water preparation group than in the matched control group. There was no any adverse event at all related to warm water preparation protocol. Conclusions: Drinking warm water dramatically reduces esophageal food retention and significantly improves the quality of esophageal preparation. This simple protocol is quite useful, safe, and cost-effective in the preparation of achalasia patients for POEM.

Improving the tolerability and safety of 1-L polyethylene glycol plus low-dose ascorbic acid for bowel preparation in a healthy population: a randomized multicenter clinical trial.

BACKGROUND AND AIMS: One-liter polyethylene glycol plus ascorbic acid (PEG-ASC) improves patient tolerability, but some patients still show low tolerability to a relatively high content of ASC. This study aimed to improve the tolerability and safety of 1-L PEG with low-dose ASC in comparison with standard 1-L and 2-L PEG-ASC. METHODS: This was a randomized, controlled, double-blinded, multicenter, noninferiority trial involving 215 healthy adults who underwent colonoscopy from June 2020 to January 2021. Efficacy, tolerability, and safety were compared among 1-L PEG with low-dose ASC (50% lower ASC concentration in group A and 25% lower ASC concentration in groups B and C) and standard 1-L and 2-L PEG-ASC with all split regimens. RESULTS: One-liter PEG with low-dose ASC (groups A-C) had similar bowel cleansing efficacies according to the Harefield Cleansing Scale and Boston Bowel Preparation Scale, without negative clinical performance, compared with standard 1-L and 2-L PEG-ASC preparation (all P > .1). One-liter PEG with low-dose ASC had better tolerability compared with 2-L PEG-ASC and less residual fluid retention in the stomach compared with 1-L PEG-ASC, proportional to the amount of ASC. No significant differences were found in the incidences of overall adverse events, mild adverse events, or death or in the occurrence of gastroduodenal erosion or ulcer in upper endoscopy. CONCLUSIONS: One-liter PEG with low-dose ASC (25%-50% reduction in dose) for bowel cleansing showed similar efficacy and safety compared with standard 1-L or 2-L PEG-ASC, better tolerability compared with 2-L PEG-ASC, and less residual gastric fluid retention compared with standard 1-L PEG-ASC. (Clinical trial registration number: KCT0005490.).

Does precutting prior to endoscopic piecemeal resection of large colorectal neoplasias reduce local recurrence? A KASID multicenter study.

BACKGROUND: It would be expected that local recurrence could be reduced by performing precutting (with sufficient margins) prior to endoscopic piecemeal mucosal resection (EPMR). We explored the clinical outcomes and local recurrence after precutting EPMR of large colorectal neoplasias. METHODS: Between January 2005 and December 2015, in total, 223 patients with colorectal neoplasias ≥ 2 cm in diameter removed via EPMR in four tertiary hospitals were enrolled. The patients were divided into a precut EPMR group (n = 62) and a non-precut EPMR group (n = 161). We retrospectively evaluated clinical outcomes and factors associated with local recurrence. RESULTS: The mean total procedure time was significantly shorter in the non-precut EPMR group than in the precut EPMR group. However, the number of pieces, and the complete resection and recurrence rates, did not differ significantly [for the latter, precut 8.1% vs. non-precut 9.9%, P = 0.668]. The complete resection rate, number of pieces, and use of argon plasma coagulation (APC) were significantly associated with the local recurrence rate on univariate analysis. In the Cox's proportional hazards model, prophylactic APC [hazard ratio 0.307, 95% confidence interval (CI) 0.114-0.823; P = 0.019] and complete resection rate (odds ratio 0.083, 95% CI 0.011-0.655; P = 0.018) were significantly associated with the local recurrence rate. CONCLUSION: Precutting prior to EPMR did not significantly reduce the local recurrence rate or the number of resected pieces. Histologically complete resection, reducing the number of pieces, and prophylactic APC seem to be important in terms of reducing local recurrence.

Reversibility of Endoscopic Features after Treatment for Eosinophilic Esophagitis.

PURPOSE: The prevalence and incidence of eosinophilic esophagitis (EoE) are increasing worldwide. Despite increased understanding of inflammatory pathogenesis, changes in endoscopic features after treatment of EoE have not been clearly described. We aimed to investigate the reversibility of endoscopic features of EoE after treatment. MATERIALS AND METHODS: Out of 58 adult subjects who were diagnosed with EoE at the Yonsei University Health System from July 2006 to August 2019, we recruited 33 subjects (30 males; mean age: 42 years) whose pre-treatment and post-treatment endoscopic images were available. Endoscopic features included both inflammatory and fibrostenotic features. Exudate, edema, furrow, and crepe paper-like mucosa were classified as inflammatory features. Ring and stricture were classified as fibrostenotic features. We compared changes in endoscopic features after treatment for EoE. RESULTS: After treatment, clinical symptoms improved in all patients. The following endoscopic features were observed before treatment: furrow (81.8%), edema (90.9%), exudate (42.4%), ring (27.3%), crepe paper-like mucosa (15.2%), and stricture (3.0%). Endoscopic remission was achieved in 21 patients (63.6%). Inflammatory features were reversible (72.7%, p<0.001), whereas fibrostenotic features were not (10%, p=0.160). Exudate had resolved in 92.9% of patients, edema in 70% and furrow in 88.9%. Ring and stricture persisted in almost all of the patients (9/10) who had these endoscopic features before treatment. CONCLUSION: We outlined the reversibility of endoscopic inflammatory features of EoE. Fibrostenotic features were irreversible after esophageal remodeling in patients with EoE. However, further validation studies with long-term follow-up are needed.

Risk of Cancer Following the Use of N-Nitrosodimethylamine (NDMA) Contaminated Ranitidine Products: A Nationwide Cohort Study in South Korea.

N-nitrosodimethylamine (NDMA), a known carcinogenic agent, was recently detected in some products of ranitidine. Several studies have investigated the detectability of NDMA, in drugs and their risks. However, only a few epidemiological studies have evaluated cancer risk from the use of such individual drugs. This study investigates the risk of cancer in ranitidine users. We conducted an observational population-based cohort study using the Health Insurance Review and Assessment databases, which contain information about the use of medicines in South Korea. The primary study cohort consisted of ranitidine users (n = 88,416). For controls, we enrolled users of famotidine, another H2-receptor antagonist in which no NDMA has been detected. A 4:1 matched cohort was constructed to compare cancer outcomes of the two groups. Our matched cohort comprised of 40,488 ranitidine users and 10,122 famotidine users. There was no statistical difference in the overall cancer risk between the ranitidine and famotidine groups (7.45% vs. 7.56%, HR 0.99, 95% CI 0.91-1.07, p = 0.716). Additionally, no significant differences were observed in the analysis of 11 single cancer outcomes. We found no evidence that exposure to NDMA through ranitidine increases the risk of cancer.

Lesion-Based Convolutional Neural Network in Diagnosis of Early Gastric Cancer.

Diagnosis and evaluation of early gastric cancer (EGC) using endoscopic images is significantly important; however, it has some limitations. In several studies, the application of convolutional neural network (CNN) greatly enhanced the effectiveness of endoscopy. To maximize clinical usefulness, it is important to determine the optimal method of applying CNN for each organ and disease. Lesion�-based CNN is a type of deep learning model designed to learn the entire lesion from endoscopic images. This review describes the application of lesion-based CNN technology in diagnosis of EGC.

Effect of histologic differences between biopsy and final resection on treatment outcomes in early gastric cancer.

BACKGROUND AND STUDY AIMS: Biopsy-based histologic diagnosis is important in determining the treatment strategy for early gastric cancer (EGC). However, there are few studies on how histologic discrepancy may affect patients' treatment outcomes. We aimed to investigate the impact of histopathologic differences between biopsy and final specimens from endoscopic resection (ER) or gastrectomy on treatment outcomes in patients with EGC. We also examined the predictive factors of histologic discrepancy. PATIENTS AND METHODS: We analyzed the data of 1851 patients with EGC treated with ER or gastrectomy. We compared the histology between biopsies and final resected specimens from ER or gastrectomy. We also examined changes in treatment outcomes according to histologic differences. RESULTS: Histologic discrepancy was observed in 11.9% of patients in the ER group and 10.7% of those in the gastrectomy group. In patients treated with ER who showed histologic discrepancy, 80.9% showed differentiated-type EGC (D-EGC) on biopsy but undifferentiated-type-EGC (UD-EGC) after ER, of which 78.9% were non-curative resection. In patients treated with gastrectomy who showed histologic discrepancy, 39% showed UD-EGC on biopsy but showed D-EGC after gastrectomy. A total of these patients had absolute and expanded indications for ER. Moderately differentiated and poorly differentiated adenocarcinoma on biopsy were predictive factors of histologic discrepancy in UD-EGC and D-EGC on final resection, respectively. CONCLUSIONS: About 10% of patients showed histologic discrepancy between biopsy and final resection with ER or gastrectomy. Histologic discrepancy can affect treatment outcomes, such as non-curative resection in ER or missing the opportunity for ER in gastrectomy.

Morphologic Restoration After Peroral Endoscopic Myotomy in Sigmoid-type Achalasia.

BACKGROUND/AIMS: Achalasia is a chronic, progressive motility disorder of the esophagus. The sigmoid-type achalasia is an advanced stage of achalasia characterized by severe dilatation and tortuous angulation of the esophageal body. Peroral endoscopic myotomy (POEM) has been reported to provide excellent clinical outcomes for achalasia, including the sigmoid type, but the restoration of esophageal morphology and function remain poorly described. The aim of our study is to investigate esophageal restoration after POEM for sigmoid-type achalasia. METHODS: From 98 patients with achalasia who underwent POEM in the Yonsei University Health System from 2013 to 2018, we recruited 13 patients with sigmoid-type achalasia (7 male; mean age 53.3 years) and assessed morphological and manometric changes in the esophagus. RESULTS: Clinical success (Eckardt score < 3) was achieved in all cases. After POEM, the average angle of esophageal tortuosity became more obtuse (91.5° vs 114.6°, P = 0.046), esophageal body diameter decreased (67.6 vs 49.8 mm, P = 0.002), and esophagogastric junction opening widened (6.4 vs 9.5 mm, P = 0.048). Patients whose esophageal tortuosity did not improve had longer durations of symptoms than patients with improvement (80.2 vs 636 months, P < 0.001). An absence of peristalsis was observed in all patients pre- and post-POEM. CONCLUSIONS: POEM resulted in excellent clinical outcomes and morphologic improvement in sigmoid-type achalasia. These results suggest that the improvement of esophageal tortuosity through POEM reflects a reduced esophageal burden.

A Lesion-Based Convolutional Neural Network Improves Endoscopic Detection and Depth Prediction of Early Gastric Cancer.

In early gastric cancer (EGC), tumor invasion depth is an important factor for determining the treatment method. However, as endoscopic ultrasonography has limitations when measuring the exact depth in a clinical setting as endoscopists often depend on gross findings and personal experience. The present study aimed to develop a model optimized for EGC detection and depth prediction, and we investigated factors affecting artificial intelligence (AI) diagnosis. We employed a visual geometry group(VGG)-16 model for the classification of endoscopic images as EGC (T1a or T1b) or non-EGC. To induce the model to activate EGC regions during training, we proposed a novel loss function that simultaneously measured classification and localization errors. We experimented with 11,539 endoscopic images (896 T1a-EGC, 809 T1b-EGC, and 9834 non-EGC). The areas under the curves of receiver operating characteristic curves for EGC detection and depth prediction were 0.981 and 0.851, respectively. Among the factors affecting AI prediction of tumor depth, only histologic differentiation was significantly associated, where undifferentiated-type histology exhibited a lower AI accuracy. Thus, the lesion-based model is an appropriate training method for AI in EGC. However, further improvements and validation are required, especially for undifferentiated-type histology.

Efficacy of a Multiplex Paclitaxel Emission Stent Using a Pluronic® Mixture Membrane versus a Covered Metal Stent in Malignant Biliary Obstruction: A Prospective Randomized Comparative Study.

BACKGROUND/AIMS: A drug-eluting stent for unresectable malignant biliary obstruction was developed to increase stent patency by preventing tumor ingrowth. The safety and efficacy of a new generation of metallic stents covered with a paclitaxel-incorporated membrane using a Pluronic® mixture (MSCPM-II) were compared prospectively with those of covered metal stents (CMSs) in patients with malignant biliary obstructions. METHODS: This study was initially designed as a prospective randomized trial but was closed early because of a high incidence of early occlusion. Therefore, the data were analyzed using the intent-to-treat method. A total of 72 patients with unresectable distal malignant biliary obstructions were prospectively enrolled. RESULTS: The two groups did not differ significantly in basic characteristics and mean follow-up period (MSCPM-II 194 days vs CMS 277 days, p=0.063). Stent occlusion occurred in 14 patients (35%) who received MSCPM-II and in seven patients (21.9%) who received CMSs. Stent patency and survival time did not significantly differ between the two groups (p=0.355 and p=0.570). The complications were mild and resolved by conservative management in both groups. CONCLUSIONS: There were no significant differences in stent patency or patient survival in MSCPM-II and CMS patients with malignant biliary obstructions.

Treatment of completely obstructed benign biliary strictures with magnetic compression anastomosis: follow-up results after recanalization.

BACKGROUND AND AIMS: Although nonsurgical methods produce high clinical success rates in the treatment of benign biliary stricture (BBS), conventional methods are not always successful in cases of severe biliary stricture or complete obstruction. Therefore, the efficacy of magnetic compression anastomosis (MCA) for treatment of refractory BBS was evaluated in a single-center, nonrandomized study. METHODS: MCA was performed in patients with BBS that was not resolved by conventional endoscopic or percutaneous treatments. One magnet was delivered through the percutaneous transhepatic biliary drainage tract, and the other advanced through 1 of 3 different routes. After magnet approximation and recanalization, an internal drainage catheter was placed for 6 months. RESULTS: This study followed 39 patients who underwent MCA after the development of postoperative or traumatic strictures. Recanalization was achieved successfully in 35 patients. There was an acceptable procedure-related adverse event of mild cholangitis in 1 patient and no procedure-related mortalities. The average elapsed time from magnet approximation to removal was 57.4 days (range, 13-182 days), and the mean follow-up period after recanalization was 41.9 months (range, 7.1-73.4 months). Restenosis after MCA recurred in 1 patient, and partial restenosis occurred in another patient, but recanalization in these patients was successful using a guidewire via the percutaneous and endoscopic tracts. CONCLUSIONS: MCA represents an alternative nonsurgical recanalization method for BBSs that cannot be treated by conventional methods. The rate of stricture recurrence after MCA was lower than that after conventional methods, likely because of the creation of a new fistula tract instead of dilation of a previous stricture.

Are new criteria for mixed histology necessary for endoscopic resection in early gastric cancer?

PURPOSE: Early gastric cancer (EGC) of mixed histology is more aggressive than other histologies. In addition, signet ring cell (SRC) mixed histology shows more submucosal invasion and greater lymph node metastasis (LNM). However, there are no criteria for endoscopic resection (ER) in mixed histology. Therefore, this study investigated whether new criteria for mixed histology are necessary for ER in EGC. METHODS: From January 2005 to December 2012, 3419 patients with EGC underwent surgery. Lesions were classified using three histological classifications: the Japanese classification; World Health Organization (WHO) classification including SRC mixed histology; and Lauren classification. The mixed type in the Lauren classification was also reclassified according to the proportion of differentiated and undifferentiated components. Clinicopathological characteristics were compared according to histological classifications, with special reference to the ER criteria. RESULTS: With the Lauren classification, 179 (5.3%) lesions were classified as mixed type, including 54 (30.2%) lesions as the differentiated-predominant mixed type. There were 361 (10.6%) lesions classified as SRC mixed histology. Mixed-type lesions in the Lauren classification and SRC mixed lesions were significantly associated with larger size and a greater LNM. Among the lesions meeting the ER criteria, 20 (1.6%) and 55 (4.7%) were categorized as mixed type by the Lauren classification and SRC mixed histology, respectively. However, there was no LNM among the lesions recategorized into mixed histology. CONCLUSIONS: Mixed histology showed no LNM among the lesions met the present ER criteria. Thus, separate criteria for mixed histology might be not necessary in the criteria for ER in EGC.