Risk Factors for a Narrow Safety Margin after Endoscopic Submucosal Dissection for Early Gastric Cancer.

INTRODUCTION: A narrow safety margin (NSM) after endoscopic submucosal dissection (ESD) is a well-recognized risk factor for local recurrence in early gastric cancer (EGC). However, only a few studies have investigated the risk factors for the development of NSM. METHODS: The medical records and pathologic specimens of patients with EGC who underwent ESD from January 2020 to December 2020 at a single tertiary hospital (Daejeon, South Korea) were reviewed. RESULTS: A total of 218 patients were enrolled and 29 had NSM (<3 mm). When comparing the NSM and the control groups, the size of the lesion, the depth of invasion, and the operating endoscopist were found to be risk factors for the development of NSM. The increased length of the subepithelial spread of the lesion was associated with a narrower safety margin. Logistic regression analysis revealed that lesion size was a risk factor for NSM, and a marginally significant difference between endoscopists was found. CONCLUSIONS: Multiple factors may need to be considered during ESD, including lesion size, invasion depth, operating endoscopist, and subepithelial spread.

Validation and Comparison of the Japanese Score and Other Scores in Patients with Nonvariceal Upper Gastrointestinal Bleeding: A Retrospective Study.

BACKGROUND: Various scoring systems have been developed to predict endoscopic intervention, mortality, and rebleeding in patients with nonvariceal upper gastrointestinal bleeding (NVUGIB); however, they have not been sufficiently validated in Korea. Therefore, this study aimed to evaluate the usefulness of several scoring systems in Korea by validating and comparing the Japanese score and other scores in Korean people with NVUGIB. METHODS: The medical records of 1,368 patients with NVUGIB were reviewed to collect statistical, clinical, laboratory, and endoscopic data. The Japanese score, ABC score, Glasgow-Blatchford Bleeding Score (GBS), and MAP score were calculated retrospectively at a single research institution. These scores for predicting the need for endoscopic intervention, mortality, and rebleeding were calculated and evaluated using the area under the receiver operating characteristic curve. RESULTS: Of 1,368 patients, 88.5% required endoscopic intervention, 4.1% died within 30 days, and 12.6% experienced rebleeding. The Japanese score was effective for predicting endoscopic intervention, and the ABC score was best for predicting 30-day mortality. Sex, age, hematemesis, blood urea nitrogen, and American Society of Anesthesiologists score were found to be predictors of the need for endoscopic intervention. CONCLUSION: The Japanese score did not prove useful in Koreans with upper gastrointestinal bleeding. Additional research is needed due to the limitations of a retrospective study conducted in a single research institute.

A comparative study of scoring systems that accurately predict the prognosis of lower gastrointestinal bleeding.

PURPOSE: Lower gastrointestinal (GI) bleeding can be fatal; therefore, several scoring systems have been developed to predict its prognosis. We compared the mortality predictions and evaluated the usefulness of various scoring systems. METHODS: The medical records of 3794 patients who visited the emergency department with hematochezia between January 2016 and December 2021 were retrospectively reviewed. We calculated the areas under the receiver operating characteristic curves for 30-day mortality and prolonged hospital stay (≥ 10 days) based on the age, blood tests, and comorbidities (ABC); AIMS65; Glasgow-Blatchford; Oakland; Rockall (pre-endoscopy); and SHA2PE scores and compared the predictive accuracy of each score. RESULTS: Data for 963 patients (median age, 69 years; males, 54.5%; median hospital stay, 6 days) with colonoscopy-confirmed lower GI bleeding were analyzed. The 30-day mortality rate was 3.5%; the most common causes of lower GI bleeding were ischemic colitis and diverticulum bleeding in 19.3% and 19.2% of the cases, respectively. The AIMS65 and ABC scores were superior in predicting 30-day mortality (p < 0.001). The SHA2PE score was the most accurate predictor of prolonged hospital stay (p < 0.001). Through multivariate regression analysis, 30-day mortality was correlated with albumin level ≤ 3.0 g/dL, international normalized ratio > 1.5, blood urea nitrogen level ≥ 30 mg/dL, and systolic blood pressure (SBP) < 100 mmHg. A prolonged hospital stay was correlated with liver cirrhosis, hemoglobin ≤ 10 g/dL, albumin level ≤ 3.0 g/dL, and SBP < 100 mmHg. CONCLUSION: The recently developed scoring systems accurately predict lower GI bleeding prognosis, and their usefulness in clinical decision-making was confirmed.

Outcomes of laparoscopic radiofrequency ablation versus percutaneous radiofrequency ablation for hepatocellular carcinoma.

BACKGROUND: Few studies have compared the therapeutic outcomes in patients with HCC who underwent laparoscopic radiofrequency ablation (LRFA) versus percutaneous radiofrequency ablation (PRFA) for hepatocellular carcinoma (HCC). Therefore, this study compared the recurrence and survival outcomes of the two RFA methods in patients with HCC. METHODS: Recurrence and overall survival outcomes were evaluated in 307 patients who underwent LRFA (n = 151) or PRFA (n = 156) as a treatment method for de novo HCC. Inverse probability of treatment weighting (IPTW) analysis was performed to reduce the impact of treatment selection bias. RESULTS: There were no significant differences in major baseline characteristics between the LRFA and PRFA groups. However, the proportion of cirrhotic patients was higher in the LRFA group, whereas the LRFA group had more tumors and a more advanced tumor-node-metastasis stage. Moreover, the mean tumor size was significantly larger in the LRFA group than in the PRFA group. In a multivariate analysis, serum albumin level, more than three tumors, and the RFA method were identified as significant predictors of recurrence-free survival. Moreover, for the overall survival of HCC patients, serum albumin levels, days of hospital stay during RFA, and the RFA method were independent predictors. In the IPTW-adjusted analysis, the LRFA group showed significantly higher recurrence-free survival and overall survival. CONCLUSIONS: Our study revealed that compared with PRFA, LRFA was associated with longer recurrence-free survival and favorable overall survival in patients with HCC. Therefore, LRFA should be considered the primary therapy in patients with HCC eligible for RFA.

Typhoid fever presenting with gastric ulcer bleeding.

BACKGROUND: Enteric fever is a systemic disease caused by Salmonella enterica serovar Typhi or Salmonella enterica serovar Paratyphi, characterized by high fever and abdominal pain. Most patients with enteric fever improve within a few days after antibiotic treatment. However, some patients do not recover as easily and develop fatal life-threatening complications, including intestinal hemorrhage. Lower gastrointestinal bleeding has been reported in 10% of cases. However, upper gastrointestinal bleeding has rarely been reported in patients with enteric fever. We present a case of gastric ulcer hemorrhage caused by enteric fever. CASE PRESENTATION: A 32-year-old woman, complaining of fever lasting four days and right upper quadrant pain and melena that started one day before admission, consulted our hospital. Abdominal computed tomography revealed mild hepatomegaly and gastroscopy revealed multiple active gastric ulcers with flat black hemorrhagic spots. The melena of the patient stopped on the third day. On the fifth admission day, she developed hematochezia. At that time, Salmonella enterica serovar Typhi was isolated from the blood culture. The antibiotic regimen was switched to ceftriaxone. Her hematochezia spontaneously resolved the following day. Finally, the patient was discharged on the 12th admission day without clinical symptoms. However, her fever recurred one month after discharge, and she was readmitted and Salmonella enterica serovar Typhi was confirmed again via blood culture. She was treated with ceftriaxone for one month, and was discharged without complications. CONCLUSION: Our case showed that although rare, active gastric ulcers can develop in patients with enteric fever. Therefore, upper and lower gastrointestinal bleeding should be suspected in patients with enteric fever, especially showing relapsing bacteremia.

Effect of Diminutive Adenoma with High-Grade Dysplasia on Surveillance Colonoscopy Interval.

BACKGROUND: Colonoscopy surveillance guidelines set the surveillance schedule based on polyp characteristics. Polyps with high-grade dysplasia (HGD) require 3 years of follow-up regardless of size. However, it is unclear whether patients with diminutive polyps (≤5 mm) with HGD have a higher risk. We evaluated the effect of diminutive adenoma with HGD on adenoma occurrence. METHODS: From January 2015 to December 2017, patients who underwent index and surveillance colonoscopy were retrospectively screened. The patients were grouped into no adenoma group, low-risk (patients with ≤2 low-grade dysplasia [LGD]), diminutive HGD, and high-risk (HGD >5 mm, ≥3 adenomas) groups according to the index colonoscopy results. Each group was analyzed using logistic analysis. RESULTS: The mean follow-up period was 22.47 months. Altogether, 610 (50.45%) patients had LGD and 152 (12.5%) had HGD. Among them, 61 (5.0%) patients had a diminutive polyp with HGD. Analysis of the risks of developing advanced adenoma in the surveillance colonoscopy showed that compared to the no adenoma group, the diminutive HGD group did not show a significant risk (odds ratio [OR] = 1.503 [0.449-5.027], p = 0.509), while the high-risk group showed a significant risk (OR = 2.044 [1.015-4.114], p = 0.045). CONCLUSIONS: Diminutive adenoma with HGD increased the risk of adenoma on surveillance colonoscopy, and in the case of advanced adenoma, the risk was increased, but it was not statistically significant.

Validation and modification of existing mortality prediction models for lower gastrointestinal bleeding: a retrospective study.

BACKGROUND: Lower gastrointestinal bleeding (LGIB) often subsides without medical intervention; however, in some cases, the bleeding does not stop and the patient's condition worsens. Therefore, predicting severe LGIB in advance can aid treatment. This study aimed to evaluate variables related to mortality from LGIB and propose a scoring system. METHODS: In this retrospective study, we reviewed the medical records of patients who visited the emergency room with hematochezia between January 2016 and December 2020. Through regression analysis of comorbidities, medications, vital signs, laboratory investigations, and duration of hospital stay, variables related to LGIB-related mortality were evaluated. A scoring system was developed and the appropriateness with an area under the receiver operating characteristics curve (AUROC) was evaluated and compared with other existing models. RESULTS: A total of 932 patients were hospitalized for LGIB. Variables associated with LGIB-related mortality were the presence of cancer, heart rate > 100 beats/min, blood urea nitrogen level ≥ 30 mg/dL, an international normalized ratio > 1.50, and albumin level ≤ 3.0 g/dL. The AUROCs of the models CNUH-4 and CNUH-5 were 0.890 (p < 0.001; cutoff, 2.5; 95% confidence interval, 0.0851-0.929) and 0.901 (p < 0.001; cutoff, 3.5; 95% confidence interval, 0.869-0.933), respectively. CONCLUSIONS: The model developed for predicting the risk of LGIB-related mortality is simple and easy to apply clinically. The AUROC of the model was better than that of the existing models.

Subepithelial spread of early gastric cancer is common and extends more than expected.

BACKGROUNDS: The clinical significance of subepithelial (SE) spread from early gastric cancer (EGC) is poorly understood. Thus, we evaluated the proportion and extent of SE spread from EGC, as well as related risk factors. METHODS: We reviewed medical records and pathological specimens from patients with EGC who underwent surgery or endoscopic resection between January 2016 and December 2016 at Chungnam National University Hospital. RESULTS: A total of 404 patients were reviewed and SE spread was identified for 142 patients (35.1%). The presence of SE spread was associated with gender, histological type, location, endoscopic appearance, color change, presence of lymphovascular invasion, and invasion depth. Multivariable analysis revealed that SE spread was only independently associated with histological type. The distance of SE spread was significantly different between histological types, and the maximum distance was 17 mm. CONCLUSION: More than 30% of our patients with EGC had SE spread, which could reach up to 17 mm. Given the proportion of SE spread in these cases, a wider resection margin may be safe during endoscopic resection or surgery.

Which scoring system should be used for non-variceal upper gastrointestinal bleeding? Old or new?

BACKGROUND AND AIM: Several scoring systems for predicting outcomes in patients with non-variceal upper gastrointestinal bleeding (NVUGIB) have recently been devised, but not sufficiently validated. We compared the predictive accuracy of several scoring systems and assessed the usefulness of new scoring systems. METHODS: The medical records of 1048 patients with NVUGIB were reviewed to collect demographic, clinical, laboratory, and endoscopic data. The areas under the receiver operating characteristic curve (AUROCs) were calculated for the ABC, new Japanese scoring system, Progetto Nazionale Emorrhagia Digestiva (PNED), and other scores to compare their predictive accuracy for 30-day mortality, therapeutic intervention, rebleeding, and prolonged hospital stay (≥ 10 days). Outcome predictors were identified by multivariate analysis. RESULTS: The ABC, new Japanese scoring system, and PNED scores best predicted 30-day mortality (AUROC 0.907), need for therapeutic intervention (AUROC 0.707), and rebleeding (AUROC 0.874), respectively (all P < 0.001). The ABC and PNED scores were similarly better at predicting prolonged hospital stay (ABC AUROC: 0.765; PNED AUROC: 0.790; both P < 0.001). Thirty-day mortality was related to sex, systolic blood pressure (SBP), syncope, estimated glomerular filtration rate (eGFR), albumin, heart failure, disseminated malignancy, chronic obstructive pulmonary disease (COPD), and liver cirrhosis. Sex, age, SBP, hematemesis, blood urea nitrogen, and eGFR independently predicted the need for therapeutic intervention. Sex, SBP, pulse, albumin level, heart failure, disseminated malignancy, and COPD predicted rebleeding. CONCLUSION: The outcomes of patients with NVUGIB were better predicted by newly developed than by old scoring systems.

Accuracy of endoscopic size measurements of early gastric signet ring cell carcinoma.

BACKGROUND AND AIMS: Indications for endoscopic submucosal dissection (ESD) of early gastric cancer (EGC) are expanding, but signet ring cell carcinoma (SRC) is still unclear because of its unclear boundaries. The purpose of this study was to compare pathologic size and endoscopic size in SRC-type EGC and to find risk factors associated with tumor size underestimation. METHODS: Medical records of 137 patients diagnosed with SRC-type EGC between January 2009 and December 2016 at our tertiary hospital were reviewed. According to pathologic and endoscopic tumor sizes, they were classified into correct estimation, underestimation, and overestimation groups, and risk factors related to underestimation were analyzed. RESULTS: Among 137 patients with SRC-type EGC, 77 patients (56.2%) had undergone correct estimation, 43 patients (31.4%) had undergone underestimation, and 17 patients (12.4%) had undergone overestimation. Mean pathologic size (SD) was 20.1 (13.8) mm and mean endoscopic size (SD) was 17.9 (10.1) mm, the correlation coefficients were 0.919 (p < 0.001) , and there was no significant difference between the two groups. Multivariate analysis showed that tumor size more than 20 mm (OR 3.419; 95% CI 1.271-9.194; p = 0.015) and atrophy (OR 6.011; 95% CI 2.311-15.633; p = 0.001) were risk factors for tumor size underestimation. CONCLUSION: There was no significant difference in pathologic and endoscopic size in SRC-type EGC. Therefore, ESD may be considered as a therapeutic option if the size of the tumor is less than 20 mm and atrophy is not present in the surrounding mucosa.

Development and Validation of a Risk Scoring Model for Early Prediction of Severe Colon Ischemia.

BACKGROUND: Colon ischemia (CI) is injury to the intestines secondary to insufficient blood flow. Its clinical severity can range from mild to life-threatening. AIMS: To investigate predictive risk factors for CI and propose a scoring model for severe outcomes. METHODS: We retrospectively analyzed the medical records of patients admitted to Chungnam National University Hospital from January 2010 to December 2018. CI was defined as severe when patients required surgery immediately or after initial conservative management, death occurred after hospitalization, or symptoms persisted after 2 weeks. By controlling for possible confounders from the logistic regression analysis, we obtained a new risk scoring model for the early prediction of severe CI. Furthermore, using the area under the receiver operating characteristics curve (AUROC), we assessed the accuracy of the model. RESULTS: A total of 274 patients endoscopically diagnosed with CI were included, of whom 181 had severe CI. In the multivariate analysis, tachycardia, elevated C-reactive protein, Favier endoscopic classification stage ≥ 2, and history of hypertension were independently and significantly associated with severe CI. The AUROC of the model was 0.749. CONCLUSIONS: This risk scoring model based on the presence of tachycardia, elevated C-reactive protein level, unfavorable endoscopic findings by Favier's classification, and the history of hypertension could be used to predict severe CI outcomes at an early stage.

Comparison of conventional and modified endoscopic mucosal resection methods for the treatment of rectal neuroendocrine tumors.

BACKGROUND/AIM: Small rectal neuroendocrine tumors (NETs) confined to the submucosa are endoscopically resectable. Because most rectal NETs are submucosal tumors, conventional endoscopic mucosal resection (cEMR) may not result in a complete resection. This study investigated whether modified EMRs, namely endoscopic submucosal resection with ligation (ESMR-L), EMR with precutting (EMR-P), and strip biopsy are superior to cEMR for achieving histologically complete resection (HCR) of rectal NETs. METHODS: Medical records of 215 patients who were treated with endoscopic resections for rectal NETs between January 2011 and July 2019 were retrospectively enrolled. Of the patients, 110, 33, 29, and 43 underwent cEMR, ESMR-L, EMR-P, and strip biopsy, respectively. For each method, HCR and en bloc resection rates, procedure times, and complication rates were measured. RESULTS: HCR was achieved with cEMR, EMR-P, ESMR-L, and strip biopsies for 74.5%, 90.9%, 93.1%, and 90.7% of cases, respectively. The HCR rate for cEMR was inferior to those of the modified EMRs (p = 0.045 for cEMR vs. EMR-P; p = 0.031 for cEMR vs. ESMR-L; p = 0.027 for cEMR vs. strip biopsy). Among the three modified EMRs, there was no significant difference in achieving HCR (p = 1.000). En bloc resection (p = 0.096) and complication rates (p = 0.071) were not significantly different among the four EMR methods, although EMR-P required the longest procedure time (p = 0.000). CONCLUSIONS: All three modified EMRs are superior to cEMR and are equally effective for achieving HCR of rectal NETs.

Analysis of factors associated with local recurrence after endoscopic resection of gastric epithelial dysplasia: a retrospective study.

BACKGROUND: Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are widely used techniques for the treatment of gastric epithelial dysplasia. Previous studies have compared the clinical outcome of endoscopic resection for early gastric cancer, but few studies have focused on gastric dysplasia alone. This study aimed to evaluate the long-term prognosis following endoscopic procedures for gastric epithelial dysplasia, investigate differences in local recurrence rates according to the treatment modality, and identify risk factors associated with local recurrence. METHODS: In this retrospective study, local recurrence rates and risk factors associated with local recurrence were compared between 599 patients who underwent EMR and 306 who underwent ESD for gastric epithelial dysplasia from January 2011 to December 2015. RESULTS: The en bloc resection rate (32.2% vs. 100%, p < 0.001) and complete resection rate (94.8% vs. 99.0%, p = 0.003) were significantly lower in the EMR group than in the ESD group. The local recurrence rate was significantly lower in the ESD group (1.3%) than in the EMR group (4.2%; p = 0.026). There was a significantly increased risk of local recurrence, regardless of lesion location or histologic grade, in patients with lesions > 2 cm (p = 0.002) or red in color (p = 0.03). The ESD group had a significantly lower local recurrence rate, with a higher complete resection rate, than that in the EMR group (p < 0.05). In the case of recurrence after endoscopic resection, most of the recurred lesions were removed through additional endoscopic procedures; there was no difference between the two groups (p = 0.153). CONCLUSIONS: The complete resection rate was significantly higher, and the local recurrence rate was significantly lower, in patients with gastric epithelial dysplasia treated with ESD. Therefore, ESD should be considered the preferred treatment in patients with lesions > 2 cm or showing redness due to an increased risk of local recurrence and EMR may be possible for low-grade dysplasia that is less than 2 cm without surface changes such as redness, depression and nodularity.

Validation of a new risk score system for non-variceal upper gastrointestinal bleeding.

BACKGROUND: Recently, a new international bleeding score was developed to predict 30-day hospital mortality in patients with upper gastrointestinal bleeding (UGIB). However, the efficacy of this newly developed scoring system has not been extensively investigated. We aimed to validate a new scoring system for predicting 30-day mortality in patients with non-variceal UGIB and determine whether a higher score is associated with re-bleeding, length of hospital stay, and endoscopic failure. METHODS: A retrospective study was performed on 905 patients with acute non-variceal UGIB who were examined in our hospital between January 2013 and December 2017. Baseline characteristics, endoscopic findings, re-bleeding, admission, and mortality were reviewed. The 30-day mortality rate of the new international bleeding risk score was calculated using the receiver operating characteristic curves and compared to the pre-endoscopy Rockall score, AIMS65, Glasgow Blatchford score, and Progetto Nazionale Emorragia Digestiva score. To verify the variable for the 30-day mortality of the new scoring system, we performed multivariate logistic regression using our data and further analyzed the score items. RESULTS: The new international bleeding scoring system showed higher receiver operating characteristic (ROC) curve values in predicting mortality (area under ROC curve 0.958; [95% confidence interval (CI)]), compared with such as AIMS65 (AUROC, 0.832; 95%CI, 0.806-0.856; P < 0.001), PNED (AUROC, 0.865; 95%CI, 0.841-0.886; P < 0.001), Pre-RS (AUROC, 0.802; 95%CI, 0.774-0.827; P < 0.001), and GBS (AUROC, 0.765; 95%CI, 0.736-0.793; P < 0.001). Multivariate analysis was performed using our data and showed that the 30-day mortality rate was related to multiple comorbidities, blood urea nitrogen, creatinine, albumin, syncope at first visit, and endoscopic failure within 24 h during the first admission. In addition, in the high-score group, relatively long hospital stay, re-bleeding, and endoscopic failure were observed. CONCLUSION: This is a preliminary report of a new bleeding score which may predict 30-day mortality better than the other scoring systems. High-risk patients could be screened using this new scoring system to predict 30-day mortality. The use of this scoring system seemed to improve the outcomes of non-variceal UGIB patients in this study, through proper management and intervention.

Subepithelial Spread of Early Gastric Signet Ring Cell Carcinoma: How Far They Can Reach?

INTRODUCTION: Although signet ring cell carcinoma (SRC) is a poorly differentiated cancer subtype, recent studies suggest that endoscopic resection can be applied in small, mucosal early gastric SRC. However, other studies report frequent positive lines at the lateral resection margin after endoscopic treatment. Subepithelial spread beneath normal mucosa can exist in SRC, and such lesions may be the cause of positive margins after endoscopic resection. Thus, we conducted a retrospective study in order to evaluate the significance of subepithelial spread in early gastric SRC. METHOD: Medical records of early gastric SRC patients who underwent surgery or endoscopic resection from January 2011 to December 2016 at a single tertiary hospital (Daejeon, South Korea) were reviewed to examine subepithelial spread and clinical datum. Two expert pathologists reviewed all pathologic specimens, and only patients showing a pure SRC component were included. RESULTS: Eighty-six patients were initially enrolled, and subepithelial spread existed in 62 patients (72.1%). The mean distance of subepithelial spread was 1,132.1 µm, and the maximal distance was 6,000 µm. Only discoloration was significantly associated with the presence of a subepithelial spread (p < 0.05, χ2 test, and logistic regression test). Distance of subepithelial spread did not correlate with total lesion size. CONCLUSION: Subepithelial spread of early gastric SRC occurs frequently and can reach up to 6 mm. Lesion discoloration may be associated with the presence of subepithelial spread. Our results suggest that careful decision of the margin is needed when performing endoscopic resection of early gastric SRC.

Quality of Preoperative Colonoscopy Affects Missed Postoperative Adenoma Detection in Colorectal Cancer Patients.

BACKGROUND: Despite thorough preoperative screening, 19-30% of synchronous polyps or adenomas are detected after colon cancer surgery. Remnant synchronous lesions require additional colonoscopy procedures or surgery. AIM: To investigate factors of preoperative colonoscopy potentially affecting the detection of missed lesions in patients subjected to colorectal cancer surgery. METHODS: Of 1147 colorectal cancer patients subjected to curative open or laparoscopic colectomy and colonoscopy at the Chungnam National University Hospital from January 2012 to December 2016, 518 patients underwent pre- and postoperative colonoscopy. The index colonoscopy was defined as the last preoperative endoscopy performed. We analyzed pre- and postoperative medical charts for colonoscopy and pathological data. The effects of patient, procedure, and tumor factors on the postoperative adenoma detection rate, advanced adenoma detection rate, and adenoma miss rate (AMR) were analyzed. RESULTS: The overall AMR was 25.7% (95% confidence interval, 22.2-29.8%). Comparing optimal and non-optimal bowel preparation groups, the latter had greater postoperative polyp missed rate (PMR), AMR (p < 0.01), and AAMR (p = 0.272). The optimal preparation group allowed identification of more synchronous adenomas than in the fair (OR 5.72) and poor (OR 11.39) preparation groups. On univariate analysis, patient age and left-sided colectomy (p < 0.01) influenced AMR. Multivariate analysis showed that age, preoperative bowel preparation, and left colon resection influenced postoperative AMR. CONCLUSION: A better quality of index colonoscopy had a positive effect on lowering the detection rate of postoperative adenoma. Older age and suboptimal bowel preparation at the index colonoscopy and left-sided colectomy had negative effects on lowering the postoperative AMR.

Improvement of digital PCR conditions for direct detection of KRAS mutations.

BACKGROUND: In standard analytical conditions, an isolation step is essential for circulating tumor DNA (ctDNA) analysis. The necessity of this step becomes unclear with the development of highly sensitive detection methods. The aim of this study was to evaluate ctDNA mimetic nDNA detection as reference materials (RMs) using dPCR technologies either directly from serum or without serum. METHODS: To determine an absolute count of both mutation and wild-type bearing DNA molecules, genomic DNA (gDNA) and nucleosomal DNA (nDNA), which are similar in size to cell-free DNA, were evaluated. We tested 3 KRAS mutations in colorectal cancer cell lines. RESULTS: We describe the recent progress in RMs. The short DNA fragments, such as sDNA and nDNA, exhibited higher quantitative values of dPCR compared to gDNA. The efficiency between Atlantis dsDNase (AD) and Micrococcal Nuclease (MN) affects DNA quantification. Moreover, there was a significant difference in dPCR output when spiking gDNA or nDNA containing KRAS mutations into FBS compared to the dPCR output under non-FBS conditions. CONCLUSION: The matrix effect crucially affects the accuracy of gDNA and nDNA level estimation in the direct detection of mimic of patient samples. The form of reference material we proposed should be optimized for various conditions to develop reference materials that can accurately measure copy number and verify the detection of KRAS mutations in the matrix.

Endoscopic Prediction of Tumor Invasion Depth in Early Gastric Signet Ring Cell Carcinoma.

INTRODUCTION: Signet ring cell carcinoma (SRC) is a poorly differentiated cancer of the stomach. Recent studies imply that early gastric SRC can be well managed by endoscopic resection. Unfortunately, unlike differentiated cancers, the endoscopic features of early gastric SRC have not been well studied. This study evaluated the endoscopic features of early gastric SRC, as well as the risk factors for submucosal (SM) invasion. METHOD: The medical records of patients from 7 tertiary hospitals (Daejeon and Chungcheong province) were reviewed to examine endoscopic findings and clinical data. These patients underwent surgery or endoscopic resection between January 2011 and December 2016 and were divided into 2 groups (derivation group and validation group) in order to develop and validate an endoscopic scoring system for SM invasion. RESULTS: In total, 331 patients (129 in the derivation group and 202 in the validation group) were enrolled in this study. In the derivation group, the risk factors for SM invasion, namely, fold convergence, nodular mucosal change, and deep depression, were identified by logistic regression analysis (ORs 3.4, 5.9, and 6.0, p < 0.05). A depth-prediction score was created by assigning 1 point for fold convergence and 2 points for other factors. When validation lesions of 0.5 point or more were diagnosed as SM invasion, the sensitivity and specificity were 76.8-78.6% and 61.6-74.7% respectively. CONCLUSION: Fold convergence, nodular mucosal change, and deep depression are risk factors for SM invasion in early gastric SRC. Our depth-prediction scoring system may be useful for differentiating SM cancers.

Outcomes and Management Strategies for Capsule Retention: A Korean Capsule Endoscopy Nationwide Database Registry Study.

BACKGROUND: The most concerning complication of capsule endoscopy (CE) is capsule retention (CR) in the gastrointestinal (GI) tract; however, the clinical outcomes and management of patients with CR are still uncertain. AIMS: This study aimed to investigate the clinical outcomes and management of CR. METHODS: The outcomes of CR in multiple centers between October 2002 and June 2018 were retrospectively reviewed. Data on CE indication, findings, and management details were analyzed. RESULTS: A total of 2705 consecutive small-bowel CE procedures were performed. CR was detected in 20 cases (0.7%). The most common site of CR was the small bowel (19 cases), followed by the esophagus (one case). In patients who underwent CE, CR was detected in nine (0.6%) of 1397 patients with obscure GI bleeding. Further, CR occurred in 11 (6.5%) of 169 patients with Crohn's disease based on the final diagnoses after CE. Capsule retrieval was safely performed surgically in nine cases and endoscopically in six cases. The retained capsules dislodged after steroid treatment in two cases, whereas three cases of CR resolved without any intervention. In multivariate analysis, the development of abdominal symptoms after CR was a significant predictive factor for requiring endoscopic or surgical interventions for capsule extraction. CONCLUSIONS: This large multicenter study shows that CR is a rare complication with favorable clinical outcomes. Three-fourths of the patients with CR were managed with endoscopic or surgical intervention, which was required particularly in patients with abdominal symptoms after CR.

Left-Sided Colectomy: One of the Important Risk Factors of Metachronous Colorectal Adenoma After Colectomy for Colon Cancer.

BACKGROUND: Patients with a history of colonic resection for cancer have an increased risk for the development of metachronous malignant lesions. However, there is a lack of data on the detection rates of premalignant lesions during colonoscopy surveillance in these patients, and the few existing studies have shown conflicting results. AIMS: To identify the risk factor of metachronous premalignant lesions after colon cancer surgery. METHODS: We retrospectively screened consecutive patients who had undergone colonic surgery to treat colon cancer at the Chungnam National University Hospital between September 2009 and April 2014. We measured polyp, adenoma, and advanced adenoma detection rates (PDR, ADR, AADR) from the second surveillance colonoscopy in patients with left-sided colectomy (LCR) or right-sided colectomy (RCR). Multivariate analysis was performed to adjust for other confounding factors. RESULTS: A total of 348 patients were enrolled (220 LCR patients and 128 RCR patients). The PDR, ADR, and AADR in patients in the LCR and RCR groups were 56.4, 43.6, and 11.8% and 35.9, 26.6, and 9.4%, respectively. PDR and ADR in the LCR group were significantly higher than those in the RCR group. A multivariate analysis showed that male sex, hypertension, body mass index higher than 25, and LCR (odds ratio 2.090; 95% confidence interval 1.011-4.317) were associated with adenoma recurrence. CONCLUSIONS: The LCR group had a higher adenoma recurrence rate than the RCR group. Further studies are required to determine the optimal surveillance intervals according to the type of colonic resection.