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Background: The fatty acid profile of the fecal metabolome and its association with colorectal cancer (CRC) has not been fully evaluated.Aims: We aimed to compare the fecal fatty acid profiles of CRC patients and healthy controls.Methods: We enrolled 26 newly diagnosed CRC patients and 28 healthy individuals between July 2014 and August 2014 from our institute. Long- and short-chain fatty acids were extracted from fecal samples and analyzed using gas chromatography-mass spectrometry.Results: Regarding fecal long-chain fatty acids, the levels of total ω-6 polyunsaturated fatty acids and, particularly, of linoleic acid (C18:2ω-6) were significantly higher in male CRC patients than in healthy men (2.750 ± 2.583 vs. 1.254 ± 0.966 µg/mg feces, P = 0.040; 2.670 ± 2.507 vs. 1.226 ± 0.940 µg/mg feces, P = 0.034, respectively). In addition, the levels of total monounsaturated fatty acid and, particularly, of oleic acid (C18:1ω-9) were significantly higher in male CRC patients than in healthy men (1.802 ± 1.331 vs. 0.977 ± 0.625 µg/mg feces, P = 0.027; 1.749 ± 1.320 vs. 0.932 ± 0.626 µg/mg feces, P = 0.011, respectively). However, those differences were not shown in female gender. The level of fecal short-chain fatty acids was not different between CRC patients and healthy controls.Conclusions: There were changes in the profiles of fecal fatty acid metabolomes in CRC patients compared to healthy controls, implying that fecal fatty acids could be used as a novel screening tool for CRC. [ABSTRACT FROM AUTHOR]

Background: Endoscopic submucosal dissection (ESD) with snaring (hybrid ESD) bridges the gap between ESD and endoscopic mucosal resection. We evaluated factors predictive of en bloc and complete resection of large colorectal neoplasms using hybrid ESD.Methods: This was a prospective clinical study of 78 patients who underwent hybrid ESD for excision of colorectal neoplasms (≥ 2 cm) between May 2015 and September 2016 at six university hospitals. We evaluated lesion and patient characteristics, endoscopist experience level (< 50 or ≥ 50 cases with colorectal ESD), and technical factors such as concurrent fibrosis, completion of a circumferential incision, degree of submucosal dissection (< 50 or ≥ 50%), and visualization during snaring (< 50 or ≥ 50%).Results: Multivariate analyses showed that the en bloc resection rate was significantly related to the degree of visualization during snaring (odds ratio (OR) 7.811, 95% confidence interval [CI] 1.722-35.426; p = 0.008) and the presence of fibrosis (OR 0.258, 95% CI 0.68-0.993; p = 0.049). The complete resection rate was significantly related to the colorectal ESD endoscopist skill level (OR 5.626, 95% CI 1.485-21.313; p = 0.011) and gross lesion type (OR 0.145, 95% CI 0.022-0.936; p = 0.042). When all three technical factors, i.e., completion of circumferential incision, ≥ 50% submucosal dissection, and ≥ 50% visualization during snaring, were satisfied performing hybrid ESD, the en bloc resection rate (87.5%) was similar to that of ESD.Conclusions: Visualization during snaring, presence of fibrosis, gross lesion type, and endoscopist colorectal ESD experience level affect en bloc or complete resection of large colorectal neoplasia using hybrid ESD. [ABSTRACT FROM AUTHOR]

The clinical usefulness of repeat colonoscopic polypectomy in patients with numerous polyps has not been sufficiently determined. We aimed to analyze the clinical outcomes of colonoscopic polypectomy with surveillance colonoscopies in patients with ≥ 10 polyps. We reviewed the medical records of 152 patients who underwent polypectomy of ≥ 10 polyps at the baseline colonoscopy. We investigated polyp number, polyp size, polypectomy method, procedure time, and adverse events of the baseline colonoscopy. We also investigated the frequency and interval of surveillance colonoscopies and their findings. The mean number of polyps detected at the baseline colonoscopy was 20.0, of which 16.0 polyps were endoscopically resected. The mean size of the largest polyp was 13.4 mm. The mean procedure time was 54.9 min. Post-polypectomy bleeding occurred in 6 (3.9%) patients, all of whom were treated conservatively. No patients developed perforation. With an increasing number of surveillance colonoscopies, the number of detected polyps and the procedure time decreased. Surveillance colonoscopies identified colorectal cancer only in three patients (2.0%), all of which were mucosal cancers that could be curatively treated by polypectomy. Colonoscopic polypectomy with repeat surveillance colonoscopies is a clinically effective, efficient, and safe management option in patients with ≥ 10 polyps. [ABSTRACT FROM AUTHOR]

A correction to the article "Is Endoscopic Closure With Clips Effective for Both Diagnostic and Therapeutic Colonoscopy-Associated Bowel Perforation?" that was published in the April 17, 2010 issue is presented.

The original version of the article unfortunately contained errors in author affiliation. Affiliation of third and ninth author was incorrectly assigned. [ABSTRACT FROM AUTHOR]

Background: Owing to an increased number of colonoscopy screenings, the incidence of diagnosed rectal neuroendocrine tumors (NETs) has also increased. Tumor size is one of the most frequently regarded factors when selecting treatment; however, it may not be the determinant prognostic variable. We aimed to evaluate oncological outcomes according to the treatment modality based on the size of rectal NETs. Methods: A retrospective analysis was performed on patients who were treated for rectal NETs between March 2000 and January 2016 at the Asan Medical Center, Seoul, Korea. Patients who underwent endoscopic removal, local surgical excision, and radical resection were included. The primary outcome was recurrence-free survival (RFS). Data were specified and analyzed following the 2019 World Health Organization classification (WHO). Results: A total of 644 patients were categorized under three groups according to the treatment modality used: endoscopic removal (n = 567), surgical local excision (n = 56), and radical resection (n = 21). Of a total of 35 recurrences, 27 were local, whereas eight were distant. The RFS rate did not differ significantly between the treatment groups in the same tumor-size group (≤ 1 cm group: P =.636, 1–2 cm group: P =.160). For T1 tumors, RFS rate was not different between local excision and radical resection (≤ 1 cm group: P =.452, 1–2 cm group: P =.700). Depth of invasion, a high Ki-67 index, and margin involvement were confirmed as independent risk factors for recurrence. Among patients treated with endoscopic removal, endoscopic biopsy was a significant factor for worse RFS (P <.001), while tumor size did not affect the RFS. Conclusion: The current guideline recommends treatment options according to tumor size. However, more oncologically important prognostic factors include muscularis propria invasion and a higher Ki-67 index. [ABSTRACT FROM AUTHOR]

Background: Chronic viral hepatitis is associated with a wide range of extrahepatic diseases; however, evidence on a link between chronic viral hepatitis and colorectal neoplasia is still lacking. Aims: To analyze the association between chronic viral hepatitis and prevalence of colorectal neoplasia. Methods: A systematic review of articles published in the MEDLINE, EMBASE, and Cochrane Library between 2000 and 2020 was performed. Subgroup analyses based on the types of colorectal neoplasia and the etiology of chronic viral hepatitis were conducted. Results: Twelve eligible studies with 48,428 hepatitis B virus (HBV) patients and 46,561 hepatitis C virus (HCV) patients were included. Chronic viral hepatitis was significantly associated with an increased risk of both colorectal adenoma (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.16–2.02; I2 = 83%) and colorectal cancer (CRC) (OR, 1.32; 95% CI, 1.08–1.61; I2 = 94%). The etiology of chronic viral hepatitis was an independent factor related to heterogeneity for CRC subgroup analysis revealed an increased risk of CRC in both HBV (OR, 1.18; 95% CI, 1.09–1.27; I2 = 37%) and HCV (OR, 1.88; 95% CI, 1.78–1.97; I2 = 0%). HCV was associated with an increased risk of colorectal adenoma (OR, 1.48; 95% CI, 1.22–1.79; I2 = 0%); however, HBV was not associated with an increased risk of colorectal adenoma and had considerable heterogeneity (OR, 1.65; 95% CI, 0.88–3.09; I2 = 90%). Conclusion: Our meta-analysis showed that chronic viral hepatitis is associated with an increased risk of colorectal neoplasia. The strategy of stricter screening colonoscopy may benefit from patients with chronic viral hepatitis. [ABSTRACT FROM AUTHOR]

Background: The Rutgeerts score is used to predict postoperative recurrence in CD patients after ileocolic resection and is primarily based on endoscopic findings at the neoterminal ileum. However, the optimal assessment of anastomotic ulcers (AUs) remains subject to debate. Aims: We aimed to investigate the association between anastomotic ulcers (AUs) and endoscopic recurrence in postoperative Crohn's disease (CD) patients. Methods: This single-center retrospective study, conducted between 2000 and 2016, evaluated postoperative CD patients with endoscopic remission at the first ileocolonoscopy within 1 year after ileocolic resection and those who underwent subsequent ileocolonoscopic follow-up. The study outcome was the clinical significance of AUs in predicting endoscopic recurrence. Results: Among 116 patients who were in endoscopic remission defined as the RS of i0 to i1 at the index postoperative ileocolonoscopy, 84.5% (98/116) underwent subsequent ileocolonoscopies. During the median 30.0 months (interquartile range, 21.3–53.3) of follow-up after the first ileocolonoscopy, 56.1% (55/98) of patients showed endoscopic recurrence. Furthermore, 65.8% (48/73) with AUs and 75.5% (40/53) with major AUs, defined as either an ulcer occupying ≥ 1/4 of the circumference, ≥ 3 ulcers confined to anastomotic ring, or any ulcers extending to the ileocolonic mucosa, showed endoscopic recurrence. On multivariable analysis, AUs (adjusted hazard ratio [aHR], 4.33; 95% confidence interval [CI], 1.87–10.0; P < 0.001) and major AUs (aHR, 3.64; 95% CI, 1.95–79; P < 0.001) were associated with endoscopic recurrence. Conclusions: AUs are associated with a significantly high risk of endoscopic recurrence in postoperative CD patients who are in endoscopic remission. [ABSTRACT FROM AUTHOR]

Background: A sessile-serrated adenoma (SSA) has a high risk for incomplete resection. Little is known regarding how to immediately detect remnant SSA tissue after endoscopic resection. We investigated the usefulness of narrow-band imaging (NBI) to detect remnant SSA tissue after endoscopic mucosal resection (EMR). Methods: We performed a prospective randomized study on 138 patients who had suspicious SSA on colonoscopy at five centers. After EMR on the suspected SSA determined on the endoscopic morphology, all lesions were randomized into two inspection methods, NBI and white light endoscopy (WLE), to detect remnant tissue on the resected margin. If remnant tissue was detected, an additional resection was performed. Finally, we obtained quadrant biopsies on the resection margin to evaluate the incomplete resection. The proportion of incomplete resection was calculated by combining the detection of remnant tissue and the positivity of SSA cells on the final quadrant biopsies. The primary outcome was the proportion of remnant tissue detection, and the secondary outcome was the proportion of incomplete resection of SSA. Results: In all, 145 lesions from 138 patients were removed. The diagnostic rate of SSA was 87.6% (127/145). After randomization, NBI inspection was performed on 69 lesions, and WLE inspection was performed on 76 lesions. The histologic diagnostic rate of SSA was 89.9% (62/69) in the NBI group and 85.5% (65/76) in the WLE group (p > 0.05). There were no significant differences in the detection of remnant tissue (12.9% (8/62) vs. 15.4% (10/65), p > 0.05), the proportion of SSA in remnant tissue (11.3% (7/62) vs. 12.3% (8/65), p > 0.05), or the proportion of incomplete resection (6.5 (4/62) vs. 10.8 (7/65), p > 0.05) between the NBI and WLE inspection groups, respectively. Conclusion: NBI was not superior to WLE for detecting remnant SSA tissue after EMR and could not decrease the proportion of incomplete resection of SSA. [ABSTRACT FROM AUTHOR]

For the sensitive diagnosis of colorectal cancer lesions, advanced molecular imaging techniques using cancer-specific targets have emerged. However, issues regarding the clearance of unbound probes and immunogenicity remain unresolved. To overcome these limitations, we developed a small-sized scFv antibody fragment conjugated with FITC for the real-time detection of colorectal cancer by in vivo molecular endoscopy imaging. A small-sized scFv fragment can target colon cancer secreted protein-2 (CCSP-2), highly expressed in colorectal adenocarcinoma tissues; moreover, its full-length IgG probe has been used for molecular imaging previously. To assess the efficacy of anti-CCSP-2 scFv-FITC, surgical specimens were obtained from 21 patients with colorectal cancer for ex vivo molecular fluorescence analysis, histology, and immunohistochemistry. Orthotopic mice were administered with anti-CCSP-2 scFv-FITC topically and intravenously, and distinct tumor lesions were observed by real-time fluorescence colonoscopy. The fluorescence imaging of human colon cancer specimens allowed the differentiation of malignant tissues from non-malignant tissues (p < 0.05), and the CCSP-2 expression level was found to be correlated with the fluorescence intensity. Here, we demonstrated the feasibility and safety of anti-CCSP-2 scFv-FITC for molecular imaging as well as its potential in real-time fluorescence colonoscopy for the differential diagnosis of tumor lesions. [ABSTRACT FROM AUTHOR]

Small rectal neuroendocrine tumors (NETs) can be treated using cap-assisted endoscopic mucosal resection (EMR-C), which requires additional effort to apply a dedicated cap and snare. We aimed to evaluate the feasibility of a simpler modified endoscopic mucosal resection (EMR) technique, so-called anchored snare-tip EMR (ASEMR), for the treatment of small rectal NETs, comparing it with EMR-C. We retrospectively evaluated 45 ASEMR and 41 EMR-C procedures attempted on small suspected or established rectal NETs between July 2015 and May 2020. The mean (SD) lesion size was 5.4 (2.2) mm and 5.2 (1.7) mm in the ASEMR and EMR-C groups, respectively (p = 0.558). The en bloc resection rates of suspected or established rectal NETs were 95.6% (43/45) and 100%, respectively (p = 0.271). The rates of histologic complete resection of rectal NETs were 94.1% (32/34) and 88.2% (30/34), respectively (p = 0.673). The mean procedure time was significantly shorter in the ASEMR group than in the EMR-C group (3.12 [1.97] vs. 4.13 [1.59] min, p = 0.024). Delayed bleeding occurred in 6.7% (3/45) and 2.4% (1/41) of patients, respectively (p = 0.618). In conclusion, ASEMR was less time-consuming than EMR-C, and showed similar efficacy and safety profiles. ASEMR is a feasible treatment option for small rectal NETs. [ABSTRACT FROM AUTHOR]

We aimed to investigate the endoscopic features and clinical course of CMV gastroenterocolitis in immunocompetent patients. We reviewed the medical records and endoscopic images of 86 immunocompetent patients with CMV gastroenterocolitis. Immunocompetent patients were defined as those without congenital or acquired immunodeficiency syndrome, use of anti-cancer chemotherapeutic and immunosuppressive agents, and inflammatory bowel diseases. The mean age was 65.5 ± 11.8 years and 53 (61.6%) were male. Sixty-eight (79.1%) patients had comorbidities. Upper gastrointestinal-dominant, small bowel-dominant, and colon-dominant types were observed in 19, 7, and 60 patients, respectively. Endoscopic features could be classified into discrete ulcerative type with/without exudate and diffuse erythematous type with/without exudate. Antiviral treatment with ganciclovir was initiated in 51 patients (59.3%), 40 of whom improved and 1 improved after changing ganciclovir to foscarnet. Thirty-three patients (38.4%) improved without antiviral treatment. Surgery was necessary in two patients because of colon perforation before antiviral treatment. Another two patients underwent surgery because of sigmoid stricture and cecal perforation during antiviral treatment. Endoscopic type was not associated with clinical outcomes, such as surgery and death. CMV gastroenterocolitis in immunocompetent patients mostly occur in older patients with comorbidities, and the endoscopic features vary with no association with clinical outcomes. [ABSTRACT FROM AUTHOR]

The endoscopic features between herpes simplex virus (HSV) and cytomegalovirus (CMV) esophagitis overlap significantly, and hence the differential diagnosis between HSV and CMV esophagitis is sometimes difficult. Therefore, we developed a machine-learning-based classifier to discriminate between CMV and HSV esophagitis. We analyzed 87 patients with HSV esophagitis and 63 patients with CMV esophagitis and developed a machine-learning-based artificial intelligence (AI) system using a total of 666 endoscopic images with HSV esophagitis and 416 endoscopic images with CMV esophagitis. In the five repeated five-fold cross-validations based on the hue–saturation–brightness color model, logistic regression with a least absolute shrinkage and selection operation showed the best performance (sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under the receiver operating characteristic curve: 100%, 100%, 100%, 100%, 100%, and 1.0, respectively). Previous history of transplantation was included in classifiers as a clinical factor; the lower the performance of these classifiers, the greater the effect of including this clinical factor. Our machine-learning-based AI system for differential diagnosis between HSV and CMV esophagitis showed high accuracy, which could help clinicians with diagnoses. [ABSTRACT FROM AUTHOR]

Background: Previous studies have shown vitamin D status to be associated with disease activity in patients with inflammatory bowel disease (IBD), but its influence on the clinical course of IBD has not been established. Aims: We aimed to analyze whether the serum 25-hydroxyvitamin D3 [25(OH)D] status is associated with clinical characteristics and affects the risk of surgery in patients with IBD. Methods: From the IBD registry of the Asan Medical Center, we identified all patients who had at least one 25(OH)D measurement; we then analyzed the association between clinical factors and 25(OH)D status. 25(OH)D was considered borderline deficient, deficient, and severely deficient at levels of < 30, < 20, and < 10 ng/mL, respectively. Results: We included 711 Crohn's disease (CD) and 764 ulcerative colitis (UC) patients who had not undergone surgery before 25(OH)D was measured. Both in CD and in UC patients, reduced 25(OH)D was associated with higher disease activity scores and CRP levels (p < 0.001). Severe 25(OH)D deficiency was associated with ileocolonic disease and complicated behavior in CD (p < 0.05) and was relevant to the disease extent in UC (p < 0.001). Additionally, severe 25(OH)D deficiency was associated with CMV colitis in patients with UC (p < 0.001). In multivariable analysis, severe deficiency of 25(OH)D was an independent risk factor for surgery in both CD (HR 1.93, 95% confidence interval [CI] 1.38–2.70) and UC (HR 2.77, 95% CI 1.14–6.74). Conclusion: Severe 25(OH)D deficiency may be a marker of a more aggressive clinical course of IBD. [ABSTRACT FROM AUTHOR]

The usage of direct oral anticoagulants (DOACs) to prevent and treat thromboembolic events is gradually increasing. We aimed to evaluate the outcomes of patients taking DOACs after polypectomy. We retrospectively reviewed 131 patients taking DOACs and 270 taking clopidogrel who underwent polypectomy between November 2010 and December 2017. The risk of delayed postpolypectomy bleeding (PPB) was evaluated and compared. A total of 989 polyps were removed (320 polyps in the DOAC and 669 polyps in the clopidogrel group). DOACs and clopidogrel were discontinued for 2.8 ± 1.7 days and 5.8 ± 2.5 days before polypectomy, respectively. DOACs and clopidogrel were restarted on 1.6 ± 2.9 days and 1.7 ± 1.1 days after polypectomy, respectively. According to per polyp analysis, delayed PPB rate was 1.6% in both groups (p = 0.924). Logistic regression analysis was performed after propensity score matching and revealed that DOACs did not increase the delayed PPB risk compared to clopidogrel (OR 0.929, 95% CI 0.436–1.975, p = 0.847). With the majority following the antithrombotic discontinuation guidelines, the incidence of delayed PPB was 3.1% in the patients taking DOACs. The delayed PPB risk was not greater in those taking DOACs than in those taking clopidogrel. [ABSTRACT FROM AUTHOR]

Background: Biopsies with conventional forceps beyond the operating range are difficult and cumbersome. Thus, we developed a new bendable forceps for improved access to gastrointestinal lesions and evaluated its technical feasibility. Methods: A bendable forceps was constructed with two channels and a two-stage knob. The bending motion-related structures were designed to improve the range of motion. For the evaluation of the forceps, we used 2 gastrointestinal simulators: an ex vivo porcine model, and an in vivo porcine model with some difficult endoscopic biopsy cases. All evaluations were performed by 5 expert endoscopists and an expert pathologist. Results: Compared with the conventional forceps, the bendable forceps had greater efficacy in the simulator (6.2 ± 0.4 vs. 1.96 ± 0.2, p < 0.001), ex vivo porcine model (6.33 ± 0.52 vs. 4.25 ± 0.89, p < 0.001), and in vivo porcine model (6.33 ± 0.52 vs. 4.25 ± 0.89, p < 0.001); greater safety in the simulator (1.92 ± 0.13 s vs. 4.88 ± 0.50 s, p < 0.001), ex vivo porcine model (2.02 ± 0.15 s vs 4.66 ± 0.27 s, p < 0.001), and in vivo porcine model (2.02 ± 0.15 s vs. 4.08 ± 0.70 s, p = 0.002); and larger specimens in the ex vivo porcine model (3.92 ± 0.03 mm vs. 3.85 ± 0.07 mm, p = 0.020). Conclusions: This study showed that compared with the conventional forceps, the bendable forceps was effective and safe to use for accessing difficult lesions in the three models. We believe that the bendable forceps serves as a useful supplementary diagnostic tool for accessing difficult lesions. However, further validation of its usefulness in the human body is needed. [ABSTRACT FROM AUTHOR]

Purpose: A modified endoscopic mucosal resection (EMR) technique, Tip-in EMR, was recently introduced to enhance the complete resection of colorectal neoplasia (CRN). We aimed to evaluate the feasibility of Tip-in EMR for flat CRNs. Methods: From January to September 2018, conventional or Tip-in EMR was consecutively performed for 112 flat CRNs ≥ 10 mm in diameter. Tip-in EMR was performed when en bloc snaring was impossible with conventional EMR or when a lesion was inadequately lifted owing to a previous forceps biopsy. We retrospectively collected the clinical, procedural, and histologic data of the conventional and Tip-in EMR groups and compared the en bloc resection rate, complete resection rate, and complications between the two groups. Results: Among 112 flat CRNs of 80 patients, conventional EMR and Tip-in EMR were performed for 74 and 38 lesions, respectively. The median lesion size was 12 (10–27) mm. Tip-in EMR was superior to conventional EMR in terms of en bloc resection (94.7% vs. 77.0%, p = 0.018) and histologic complete resection (76.3% vs. 54.1%, p = 0.022). There was no difference in postprocedural bleeding between the two groups; however, overall adverse events, including bleeding and postpolypectomy electrocoagulation syndrome, were more frequent in the Tip-in EMR group. Conclusions: Tip-in EMR is a feasible technique for flat colorectal lesions ≥ 10 mm and is superior to conventional EMR with respect to en bloc and complete resection rates. The safety profiles of Tip-in EMR and conventional EMR should be compared via large-scale prospective studies. [ABSTRACT FROM AUTHOR]

Background: Coexistence of colorectal neoplasia and atherosclerotic cardiovascular disease has been reported. Subclinical atherosclerosis can be evaluated noninvasively and easily by assessing carotid intima-media thickness (CIMT) and carotid plaque using ultrasonography.Aims: We aimed to evaluate the association between carotid ultrasonography findings and colorectal conventional adenoma (AD) in health checkup examinees.Methods: We retrospectively reviewed the medical records of health checkup examinees ≥ 40 years old who had undergone both carotid ultrasonography and colonoscopies at a single hospital between January 2012 and December 2016.Results: The median age of 4871 eligible participants was 54 years (range, 40-89). AD was found in 2009 individuals (41.2%), with a mean number of 1.9 ± 1.7 lesions. Abnormal CIMT (≥ 1 mm) and carotid plaque were found in 1366 (28.0%) and 1255 (25.8%) individuals, respectively. AD and high-risk adenoma (HRA) were observed more frequently in those with abnormal CIMT or plaque. Moreover, abnormal CIMT and plaque were independent risk factors for the presence of AD (odds ratio [OR]: 1.21, 95% confidence interval [CI]: 1.06-1.39, P = 0.006; OR: 1.24, 95% CI: 1.08-1.43, P = 0.002) and HRA (OR: 1.24, 95% CI: 1.05-1.52, P = 0.034; OR: 1.35, 95% CI: 1.10-1.65, P = 0.004), respectively.Conclusions: Abnormal CIMT and the presence of carotid plaque were significantly associated with AD and HRA, and each was an independent risk factor for AD and HRA. More careful observation might be needed during colonoscopies in individuals with abnormal carotid ultrasonographic findings. [ABSTRACT FROM AUTHOR]

We developed and validated a deep-learning algorithm for polyp detection. We used a YOLOv2 to develop the algorithm for automatic polyp detection on 8,075 images (503 polyps). We validated the algorithm using three datasets: A: 1,338 images with 1,349 polyps; B: an open, public CVC-clinic database with 612 polyp images; and C: 7 colonoscopy videos with 26 polyps. To reduce the number of false positives in the video analysis, median filtering was applied. We tested the algorithm performance using 15 unaltered colonoscopy videos (dataset D). For datasets A and B, the per-image polyp detection sensitivity was 96.7% and 90.2%, respectively. For video study (dataset C), the per-image polyp detection sensitivity was 87.7%. False positive rates were 12.5% without a median filter and 6.3% with a median filter with a window size of 13. For dataset D, the sensitivity and false positive rate were 89.3% and 8.3%, respectively. The algorithm detected all 38 polyps that the endoscopists detected and 7 additional polyps. The operation speed was 67.16 frames per second. The automatic polyp detection algorithm exhibited good performance, as evidenced by the high detection sensitivity and rapid processing. Our algorithm may help endoscopists improve polyp detection. [ABSTRACT FROM AUTHOR]

Background: Few studies have compared the costs of colorectal endoscopic submucosal dissection (ESD) and endoscopic piecemeal mucosal resection (EPMR).Aims: Here, we aimed to investigate the cost-effectiveness of these approaches by analyzing clinical outcomes and costs.Methods: Data from patients undergoing colorectal ESD and EPMR were retrospectively reviewed. Clinical outcomes (procedure time, complete resection, and recurrence) were compared, and total direct costs (procedural and follow-up) were assessed.Results: Data from 429 ESD and 115 EPMR patients were included in the analysis. The complete resection rate was significantly higher (83.9% vs. 32.2%, p < 0.001), recurrence rate was lower (0.5% vs. 7.1%, p < 0.001), procedure time was longer (55.4 ± 47.0 vs. 25.6 ± 32.7 min, p < 0.001), and total direct procedural costs at the initial resection were higher (1480.0 ± 728.0 vs. 729.8 ± 299.7 USD, p < 0.001) in the ESD group than in the EPMR group. The total number of surveillance endoscopies was higher in the EPMR group (1.7 ± 1.5 vs. 1.3 ± 1.1, p = 0.003). The cumulative total costs of ESD and EPMR were comparable at 3 and 2 years' follow-up in the adenoma and mucosal/superficial submucosal cancer subgroups, respectively.Conclusions: Colorectal ESD was associated with higher complete resection and lower recurrence rates. EPMR showed shorter procedure times and similar cumulative total direct costs. ESD or EPMR should be chosen based on both clinical outcomes and cost-effectiveness. [ABSTRACT FROM AUTHOR]

Background: Little is known about the natural history of perianal fistulas in Asian populations with Crohn's disease (CD).Aims: We investigated the incidence and outcomes of perianal CD (pCD) in Korean CD patients.Methods: A nationwide population-based cohort of 6265 CD patients diagnosed in 2010-2014 was analyzed to investigate the incidence and outcomes of pCD. The results were validated in a hospital-based cohort of 2923 CD patients diagnosed in 1981-2015. Factors associated with pCD development were analyzed. The incidence and outcomes of pCD were compared between the prebiologic and biologic eras.Results: pCD occurred in 39.2% of the population-based cohort and 56.1% of the hospital-based cohort during the median follow-up of 4.2 and 8.5 years, respectively. The cumulative incidence of pCD was 40.0% at 5 years after CD diagnosis in the population-based cohort and 62.5% at 20 years in the hospital-based cohort. In multivariate analysis, pCD development was positively associated with male sex, younger age and colonic involvement at diagnosis, early diagnosis, and CD diagnosis in the prebiologic era. The cumulative probability of proctectomy at 10, 20, and 30 years after pCD diagnosis was 2.9%, 12.2%, and 16.2%, respectively. The cumulative incidence of pCD occurring after CD diagnosis and the cumulative probability of proctectomy were significantly lower in the biologic era than in the prebiologic era (p < 0.001 and p = 0.03, respectively).Conclusions: Compared with Western patients with CD, Korean patients show a high incidence of pCD but have a low probability of proctectomy, suggesting the favorable course of pCD. [ABSTRACT FROM AUTHOR]

We aimed to develop a computer-aided diagnostic system (CAD) for predicting colorectal polyp histology using deep-learning technology and to validate its performance. Near-focus narrow-band imaging (NBI) pictures of colorectal polyps were retrieved from the database of our institution. Of these, 12480 image patches of 624 polyps were used as a training set to develop the CAD. The CAD performance was validated with two test datasets of 545 polyps. Polyps were classified into three histological groups: serrated polyp (SP), benign adenoma (BA)/mucosal or superficial submucosal cancer (MSMC), and deep submucosal cancer (DSMC). The overall kappa value measuring the agreement between the true polyp histology and the expected histology by the CAD was 0.614–0.642, which was higher than that of trainees (n = 6, endoscopists with experience of 100 NBI colonoscopies in <6 months; 0.368–0.401) and almost comparable with that of the experts (n = 3, endoscopists with experience of 2,500 NBI colonoscopies in ≥5 years) (0.649–0.735). The areas under the receiver operating curves for CAD were 0.93–0.95, 0.86–0.89, and 0.89–0.91 for SP, BA/MSMC, and DSMC, respectively. The overall diagnostic accuracy of the CAD was 81.3–82.4%, which was significantly higher than that of the trainees (63.8–71.8%, P < 0.01) and comparable with that of experts (82.4–87.3%). The kappa value and diagnostic accuracies of the trainees improved with CAD assistance: that is, the kappa value increased from 0.368 to 0.655, and the overall diagnostic accuracy increased from 63.8–71.8% to 82.7–84.2%. CAD using a deep-learning model can accurately assess polyp histology and may facilitate the diagnosis of colorectal polyps by endoscopists. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to evaluate the recurrence rate of colorectal neoplasia showing histologic lateral margin involvement after en bloc endoscopic submucosal dissection (ESD).Methods: We reviewed 527 colorectal lesions that were removed by en bloc ESD from 2005 to 2013 and followed by endoscopy. Based on the postprocedural pathologic reports, the lesions were categorized as follows: lesions with clear deep and positive lateral margins (n = 63) and lesions with R0 resection (n = 299).Results: The tumor size was 45.7 ± 21.1 mm in the lateral margin-positive group and 30.6 ± 15.1 in the R0 group (P < 0.001). Procedure time was longer in the lateral margin-positive group than in the R0 group (94.3 ± 75.1 vs. 54.1 ± 48.9 min; P < 0.001). Lateral margin positivity was associated with ESD time ≥ 120 min in the multivariate analysis. Compared with 0-I morphology, LST-G was significantly associated with the lateral margin positivity. The volume of ESD experience in endoscopists may also be associated with the lateral margin positivity. Histologic reassessment of the specimen suggested that 32.2% of lateral margin-positive cases based on the initial pathology report were false-positive lateral margin involvement. The 5-year cumulative recurrence rate was 0.6% in the R0 group and 5% in the margin-positive group (P = 0.198).Conclusions: The local recurrence rate was not higher in lateral margin-positive cases than in R0 resection cases if the colorectal epithelial neoplasia was removed in an en bloc manner using ESD. Meticulous pathologic interpretation may reduce unnecessarily frequent surveillance after en bloc ESD. [ABSTRACT FROM AUTHOR]

Background: Endoscopic resection of polyps located at the appendiceal orifice (AO) is challenging, and the feasibility and outcomes of endoscopic resection for cecal polyps involving AO are unconfirmed.Aims: We evaluated the feasibility and outcomes of endoscopic resection for cecal polyps involving AO.Methods: In this retrospective, multicenter study involving nine tertiary referral centers, we evaluated 131 patients who underwent endoscopic resection for cecal polyps involving AO.Results: The median size of polyps resected was 10 mm (range 3-60 mm). Endoscopic mucosal resection, endoscopic piecemeal mucosal resection, and endoscopic submucosal dissection were performed in 75 (57.3%), 31 (23.7%), and 5 (3.8%) patients, respectively. The en bloc resection rate was 68.7%. Endoscopic complete resection was achieved in 123 lesions (93.9%). Intraprocedural and delayed bleeding occurred in 14 (10.7%) and three patients (2.3%), respectively, and perforation occurred in two patients (1.5%). Seven patients (5.3%) underwent additional surgery because of treatment failure or recurrence. Polyps of ≥20 mm in size showed significantly higher rates of perforation and additional surgery (p < 0.05), and a lower rate of en bloc resection (p < 0.005). Patients with polyps involving ≥75% of AO circumference exhibited a significantly lower rate of en bloc resection (p < 0.001), and significantly higher rates of surgery and recurrence (p < 0.05). Recurrence during follow-up occurred in 12 patients (15.6%); polyps involving ≥75% of AO circumference were an independent risk factor for recurrence.Conclusion: Endoscopic resection of cecal polyps involving AO is safe and effective in select patients. [ABSTRACT FROM AUTHOR]

Background and Aims: Large-scale studies regarding the long-term outcomes of adalimumab (ADA) treatment in Asian patients with Crohn's disease (CD) are still scarce.Methods: We retrospectively analyzed the long-term outcomes of ADA treatment in Korean CD patients who commenced on scheduled ADA treatment at Asan Medical Center between November 2008 and July 2016. Clinical response was defined as maintaining ADA treatment without dose intensification (DI) and/or major abdominal surgery (MAS).Results: Of the 254 patients who received at least two doses of ADA at 2-week intervals as induction therapy, 250 patients (98.4%) showed an initial favorable response by week 4. Among responders, 243 patients were followed up for longer than 4 weeks and were included for further analysis. The median duration of ADA maintenance therapy was 19.4 months. At the last follow-up, 45 patients (18.5%) required DI after a median of 16.8 months and 31 (12.8%) required MAS after a median of 8.9 months. Finally, 161 patients (66.3%) were still receiving ADA without DI and/or MAS. The cumulative probability of maintaining ADA without DI and/or MAS was 81.1% at 1 year, and 36.5% at 5 years. Secondary loss of response to previous infliximab (P = 0.001) and elevated baseline C-reactive protein at starting ADA treatment (P = 0.008) were identified as independent predictors of a poor response to ADA treatment using multivariate regression analysis.Conclusions: The long-term outcome of ADA treatment in a real-life cohort of Korean patients with CD appears to be comparable to that reported in previously published Western studies. [ABSTRACT FROM AUTHOR]

Background: Incidence of and risk factors for intestinal free perforation (FP) in patients with Crohn's disease (CD) are not established.Aim: To establish rate of and risk factors for FP in a large cohort of CD patients.Methods: Medical records of CD patients who visited Asan Medical Center from June 1989 to December 2012 were reviewed. After matching the FP patients to controls (1:4) by gender, year, and age at CD diagnosis, and disease location, their clinical characteristics were compared using conditional logistic regression analysis.Results: Among 2043 patients who were included in our study cohort, 44 patients (2.15%) developed FP over a median follow-up period of 79.8 months (interquartile range 37.3-124.6), with an incidence of 3.18 per 1000 person-years [95% confidence interval (CI) 2.37-4.28]. All 44 patients underwent emergency surgery, and eight patients underwent reoperation within 12 months (8/44, 18.2%). Multivariable-adjusted analysis revealed that anti-TNF therapy [odds ratio (OR), 3.73; 95% CI 1.19-11.69; p = 0.024] was associated with an increased risk of FP.Conclusions: The incidence of FP in a large cohort of Korean CD patients was 2.15%, which was similar to that in Western reports. Anti-TNF therapy could be risk factors for FP. [ABSTRACT FROM AUTHOR]

Background: The recurrence rate after standard cold forceps polypectomy (CFP) of diminutive polyps of ≤5 mm has not been fully determined. The aim of this study was to analyze the long-term follow-up results and recurrence rate after CFP of diminutive polyps.Methods: We retrospectively reviewed the medical records of 884 (738 men; age 53 years) asymptomatic subjects who underwent surveillance colonoscopy after CFP of 1-2 diminutive adenomatous polyps. Cumulative recurrence at the CFP site and risk factors for recurrence were analyzed.Results: Overall recurrence over 59.7 months was 17 % after CFP of 1111 diminutive polyps. The rate of definite recurrence was 4 %, and probable recurrence was 13 %. Recurrence as advanced adenoma was 0.5 % (5/1111). The cumulative probabilities of recurrence at 3, 5, and 7 years after CFP were 10.0, 16.0, and 21.1 %, respectively. Multivariate analysis revealed that polyp 4-5 mm in size and right colonic polyp were risk factors for recurrence (hazard ratio [HR] 1.37; 95 % confidence interval [CI] 1.01-1.86 and HR 1.49; 95 % CI 1.08-2.04, respectively). The recurrence rate for 10 endoscopists who performed at least 50 CFPs ranged from 11.0 to 25.2 %; the probability of recurrence in those in the top half in terms of recurrence rate was 1.6-fold higher than that of those in the bottom half (95 % CI 1.17-2.19).Conclusions: Although recurrence may develop after standard CFP of diminutive polyps, recurrence as advanced adenoma is rare. Large polyp size, right colon polyp, and endoscopist are risk factors for recurrence after standard CFP. [ABSTRACT FROM AUTHOR]

Background and Aim: This study aimed to develop and validate a risk score model to estimate the probability of a metachronous advanced colorectal neoplasm (ACRN) at surveillance colonoscopy.Methods: A retrospective analysis of a prospectively obtained database of 11,042 asymptomatic subjects who underwent surveillance colonoscopy after a screening colonoscopy was conducted. Subjects were randomly divided into derivation (n = 7730) and validation sets (n = 3312). From the derivation cohort, risk factors for a metachronous ACRN were identified by a multivariable analysis. Risk points were allocated to each risk factor based on the hazard ratio to develop the Metachronous Advanced colorectal neoplasm Prediction Scoring (MAPS) model, the performance of which was assessed in the validation cohort.Results: In the derivation cohort, age, male, sessile serrated adenoma/polyp, and a high-risk CRN (ACRN or ≥3 adenomas) at screening colonoscopy were independent risk factors for a metachronous ACRN. These variables were incorporated into the MAPS model, and the risk score ranged 0-17 (high MAPS risk arbitrarily defined as 10-17). At the 3-year surveillance colonoscopy, ACRN was found in 5.1 % of the high MAPS risk group versus 3.9 % of the high-risk CRN group. The colonoscopy number needed to detect one metachronous ACRN at the 3-year surveillance was 19.5 (95 % CI 11.7-33.2) for the high MAPS risk group versus 25.8 (95 % CI 15.4-44.0) for the high-risk CRN group. These findings were similarly confirmed in the validation cohort.Conclusions: Our MAPS model based on clinical and colonoscopic parameters effectively predicts the risk of a metachronous ACRN. [ABSTRACT FROM AUTHOR]

Background and Aims: To date, no large-scale studies have evaluated long-term outcomes of infliximab (IFX) treatment in Korean patients with Crohn's disease (CD).Methods: We analyzed long-term clinical responses to IFX in 582 Korean CD patients who received scheduled IFX treatments at Asan Medical Center. Clinical responses were defined as maintaining IFX without major abdominal surgery (MAS) or dose intensification.Results: Between February 2002 and July 2015, a total of 11,990 IFX infusions were administered to 582 Korean patients with CD over a median period of 36 months. At the end of follow-up, 316 (54.3 %) were still receiving IFX without MAS (71 patients, 12.2 %) or dose intensification (86 patients, 14.8 %). IFX was stopped in 109 (18.7 %) patients because of a loss of response (48 patients, 8.2 %), adverse events (30 patients, 5.2 %), or patient preferences or problems with reimbursement (31 patients, 5.3 %). The cumulative survival for maintenance of IFX without MAS or dose intensification was 89.0, 75.9, 68.3, and 50.8 % at 1, 2, 3, and 5 years, respectively. Multivariate regression analysis identified older age at the initiation of IFX (≥40 years, P = 0.006) and a longer disease duration (≥3 years, P = 0.020) as independent positive predictors of a poorer response to IFX.Conclusions: The long-term efficacy of IFX in a large, real-life cohort of Korean patients with CD appears to be similar to that in previously published Western studies. Our findings support the early use of IFX to obtain better clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: Few studies have been conducted on the progression of mild Crohn's disease (CD). We aimed to investigate the natural course in mild CD patients with or without bowel damage, to identify predictors of bowel resection and to calculate the requirement for rescue medication. Methods: A total of 104 patients with mild activity (150 < CDAI < 220) with or without bowel damage were identified from among 1050 CD patients between January 2008 and May 2014. Univariate and multivariate analysis was used to identify factors associated with bowel resection. The cumulative probabilities of bowel resection and rescue medication such as steroids or anti-TNF agents were calculated. Results: The median follow-up duration was 28.2 months (IQR 26.7). Cumulative probabilities of bowel resection were 0.2, 11.8 and 42.4 % at 1, 3 and 5 years respectively. The CD patients with bowel damage had a higher bowel resection rate than those without bowel damage ( P < 0.001). The cumulative probabilities of corticosteroid-requirement were 3.0, 19.6 and 78.4 % of patients at 1, 3 and 5 years, respectively, and 2.1, 11.9 and 56.1 %, in terms of the cumulative probabilities of requiring anti-TNF agents. Patients with elevated CRP (>1.6 mg/dL) were more likely to undergo bowel resection ( P = 0.032). Conclusions: Even in CD patients with mild disease activity, the cumulative probability of bowel resection is not low if they have bowel damage or elevated CRP at baseline. Mild CD patients with bowel damage or elevated CRP at baseline need special attention. [ABSTRACT FROM AUTHOR]

Background and Aims: The therapeutic outcome of endoscopic submucosal dissection (ESD) for large protruding tumors has not yet been evaluated. We aimed to compare the outcomes of ESD in protruding tumors with those of laterally spreading tumors (LSTs).Methods: Endoscopic submucosal dissection was attempted in 218 patients with 220 colorectal tumors ≥30 mm in diameter (67, protruding tumors; 153, LSTs) from July 2007 to June 2014. We retrospectively reviewed patient medical records, therapeutic outcomes, and procedure-related adverse events. This study defined lesions with a height of 10 mm or more as protruding tumors and those with a height under 10 mm as LSTs.Results: The mean lesion diameter, height, and volume were 43.8, 9.5 mm, and 13.6 cm(3), respectively. The mean procedure time was 75.5 min. Deep submucosal cancer was more frequent in protruding tumors than in LSTs (11.9 vs. 2.6%, P = 0.005). Severe fibrosis was more common in protruding tumors than in LSTs (19.4 vs. 3.9%, P < 0.001). En bloc resection and complete resection rates were lower in protruding tumors than in LSTs (en bloc resection, 76.1 vs. 92.8%, P = 0.001; complete resection, 64.2 vs. 79.1%, P = 0.020). Intra- and post-procedural bleeding were more frequent in protruding tumors than in LSTs (22.4 vs. 2.6%, P < 0.001; 6.0 vs. 0.7%, P = 0.031, respectively). By multivariate analysis, protruding tumor morphology (odds ratio 1.919, P = 0.048) and tumor size ≥60 mm (odds ratio 2.490, P = 0.030) were associated with incomplete resection.Conclusions: Endoscopic submucosal dissection for protruding tumors is less effective than ESD for LSTs, with lower rate of complete resection occurring with protruding tumors. [ABSTRACT FROM AUTHOR]

Background: Experience in gastric endoscopic submucosal dissection (ESD) has been suggested as a prerequisite for performing colorectal ESD by some experts.Aims: To evaluate the feasibility of performing colorectal ESD without experience in gastric ESD.Methods: Between November 2009 and December 2013, ESD was attempted for 250 colorectal lesions by an endoscopist having extensive colonoscopy experience but no prior experience of gastric ESD. All attempts were categorized according to the chronological order of procedures: group 1, attempts 1-50; group 2, attempts 51-100; group 3, attempts 101-150; group 4, attempts 151-200; and group 5, attempts 201-250. Procedure-related outcomes were analyzed.Results: En bloc resection rate ≥80% was achieved after initial ten ESD attempts. The ESD success rate (72, 80, 90, 90, and 94% in group 1-5, respectively; p for trend = 0.001), perforation rate (14, 14, 6, 6, and 0% in group 1-5, respectively; p for trend = 0.003), and macroperforation rate (6, 6, 2, 2, and 0% in group 1-5, respectively; p for trend = 0.042) improved as experience accumulated. Performing >100 ESDs, rectal location, and absence of submucosal fibrosis were independent predictors of successful procedure.Conclusion: Colorectal ESD can be safely and effectively performed by an endoscopist having extensive experience in colonoscopy-related procedures even without previous experience of gastric ESD. Meticulous case selection for ESD novice and active supervision by expert endoscopists during the initial learning period may minimize the risk of perforation. [ABSTRACT FROM AUTHOR]

Background: The role of postoperative radiation therapy (RT) after local excision (LE) of deep submucosal invasive rectal cancer remains unclear. We evaluated the efficacy of adjuvant RT after LE of early rectal cancer with deep submucosal invasion.Methods: We screened 227 patients who underwent transanal excision or endoscopic removal of deep submucosal invasive rectal cancer between 1992 and 2012, of which 66 did not undergo radical surgery owing to the patient's preference or poor medical conditions. Of these, 35 (53 %) underwent LE alone (LE group) and 31 (47 %) received adjuvant RT after LE (LE + RT group). Nine patients in the RT group received concurrent adjuvant chemotherapy with 5-fluorouracil. Two independent pathologists reviewed histological data.Results: The mean age of patients in the LE + RT and LE groups was 59.5 ± 9.6 and 55.3 ± 11.2 years, respectively. The mean follow-up duration was 78.7 ± 66.7 months in the LE + RT group and 70.5 ± 45.7 months in the LE group. Cancer eventually recurred in six patients (9.1 %; two in the LE + RT group and four in the LE group). In five of these patients, recurrence occurred within 4 years after the initial treatment. The other patient, who was in the LE group, exhibited multiple lymph node metastases at the 116-month follow-up. Kaplan-Meier estimates of recurrence-free survival at 5 years after treatment were 96.8 % in the LE + RT group and 97 % in the LE group (P = 0.657).Conclusion: RT after LE of early rectal cancer with deep submucosal invasion might not improve recurrence-free survival compared with LE alone. [ABSTRACT FROM AUTHOR]

Background: The long-term outcomes of endoscopic resection of superficial submucosal colorectal cancer (CRC) had not been adequately compared with those of surgical resection. Aims: We aimed to compare the long-term clinical outcomes of endoscopic resection of superficial submucosal CRC to those of surgical resection. Methods: Submucosal CRC patients with a tumor depth of sm1 or less than 1 mm from the muscularis mucosa were enrolled. Patients with unfavorable histology, such as poorly differentiated cancer or lymphovascular invasion, were excluded. Recurrence-free survival and overall survival were investigated in 87 patients who underwent endoscopic resection and in 171 patients who underwent surgical resection. Results: The mean ages of the endoscopic and surgical resection groups were 59.7 and 59.8 years, respectively. Hospital stay was shorter in the endoscopic resection group (1.7 ± 1.6 vs. 8.6 ± 3.8 days; p < 0.001). The 3- and 5-year recurrence-free survival rates were 98.7 and 96.7 % in the endoscopic resection group and 98.7 and 97.5 % in the surgical resection group, respectively ( p = 0.837). The 3- and 5-year overall survival rates were 100.0 and 95.2 % in the endoscopic resection group and 98.7 and 92.8 % in the surgical resection group, respectively ( p = 0.928). Recurred cases showed an unfavorable histology that was overlooked at the time of initial resection. Conclusions: Long-term outcomes after endoscopic resection of superficial submucosal CRC are comparable to those after surgical resection. Thorough initial histopathological evaluations are needed to guarantee the correct indication for endoscopic resection of submucosal CRC. [ABSTRACT FROM AUTHOR]

Background: Cryptogenic multifocal ulcerous stenosing enteritis (CMUSE) is a rare disease that is characterized by multiple, recurring small intestinal ulcers with stenosis of unknown causes. The aim of this study was to investigate the clinical characteristics and the treatment outcomes of patients with CMUSE in Korea. Methods: We performed a multicenter study to retrospectively analyze clinical data from 20 patients who suffered from CMUSE between 1984 and 2012. Their clinical characteristics and long-term disease courses were investigated. Results: The most common initial symptom of CMUSE was abdominal pain (14/20, 70 %). Small bowel series (13/20, 65 %), double-balloon enteroscopy (12/20, 60 %), CT enterography (12/20, 60 %), and capsule endoscopy (10/20, 50 %) were used to diagnose CMUSE. The strictures of the patients were located in the jejunum (5/20, 25 %), ileum (7/20, 35 %), and both jejunum and ileum (6/20, 30 %). The number of patients in a state of remission, persistent disease, and relapse at the end of follow-up were 13/20 (65 %), 2/20 (10 %), and 5/20 (25 %), respectively. The median relapse-free survival was of 67.1 months. Seventy-five percent relapse-free survivals for female and male patients were 93 and 9 months, respectively ( P = 0.031). Conclusion: CMUSE is difficult to diagnose and is an easily relapsing disease. Female patients might have a better prognosis than male patients in terms of the relapse-free time. [ABSTRACT FROM AUTHOR]

Objectives:Digital rectal examination (DRE) is a simple clinical method to diagnose anorectal disorders. High-resolution antorectal manometry (HRAM) based on a spatiotemporal plot is expected to promote improved diagnostic accuracy. However, there are no reports comparing the effectiveness of DRE and HRAM. The aim of our study was therefore to evaluate the diagnostic value of DRE compared with HRAM.Methods:A total of 309 consecutive patients with chronic constipation (n=268) or fecal incontinence (n=41) who underwent a standardized DRE, HRAM, and balloon expulsion test were enrolled in this study. The diagnostic yield of DRE compared with HRAM was determined, and agreement between DRE and HRAM data was evaluated.Results:Of the constipated patients, 207 (77.2%) were diagnosed with dyssynergia using HRAM. The sensitivity, specificity, and positive predictive value of DRE in the diagnosis of dyssynergia were 93.2%, 58.7%, and 91.0%, respectively, and moderate agreement was seen between the two modalities (κ-coefficient =0.542, P<0.001). In patients with fecal incontinence, there was moderate agreement in terms of anal squeeze pressure between the two modalities (κ-coefficient =0.418, P=0.006); however, there was poor agreement for anal resting tone (κ-coefficient =0.079, P=0.368).Conclusions:DRE shows high sensitivity and positive predictive value in detecting dyssynergia compared with HRAM, and could therefore be used as a bedside screening test for the diagnosis of this disorder. Further studies are warranted to evaluate the correlation between DRE and HRAM in assessing anal sphincter pressure. [ABSTRACT FROM AUTHOR]

Background: Current guidelines for the surveillance colonoscopy interval are largely based on the most recent colonoscopy findings. Aim: We aimed to evaluate differences in the probability of high-risk neoplasm recurrence according to the two previous colonoscopy findings. Methods: This was a retrospective cohort study from a tertiary-care center. A total of 4,143 subjects who underwent three or more colonoscopies for screening or surveillance purposes from January 2001 to December 2011 were enrolled. We compared the probability of high-risk neoplasm detection on follow-up colonoscopies after the second colonoscopy based on risk categories in both the second and first colonoscopies. Results: At the final colonoscopy, 370 participants (8.9 %) had high-risk neoplasms. In patients with a normal second colonoscopy, the probability of high-risk neoplasm recurrence was different between those with normal, low-risk, and high-risk findings at the first colonoscopy (3.8, 6.8, and 17.7 %, respectively). The hazard ratio of a high-risk neoplasm at the final colonoscopy for patients with a normal second and low-risk first colonoscopy over a normal second and normal first colonoscopy was 3.07 (95 % CI 2.04-4.64, P < 0.001). The hazard ratio of high-risk neoplasm at the final colonoscopy for patients with a normal second and high-risk first colonoscopy over a normal second with normal first colonoscopy was 7.88 (95 % CI 4.90-12.67, P < 0.001). Conclusions: The rate of high-risk colorectal neoplasm recurrence differs according to the two previous colonoscopy findings. Therefore, surveillance intervals could be adjusted not just only by the most recent colonoscopy findings but also by considering two previous colonoscopy findings. [ABSTRACT FROM AUTHOR]

Background: The optimal colon-cleansing method after failure of bowel preparation (BP) for colonoscopy has not been established. Aims: We aimed to compare BP rescue methods after failed initial BP and to identify risk factors for rescue BP failure. Methods: Eighty-five patients with BP failure after 4 L polyethylene glycol (PEG) ingestion were prospectively enrolled from March 2008 to March 2012. A second colonoscopy was performed either on the same day after ingestion of another 2 L PEG (group A) or 1 week later after ingestion of 4 L PEG plus 20 mg oral bisacodyl (group B). Differences between groups in terms of BP quality and risk factors for a poor BP on the second colonoscopy were investigated. Results: Median patient age was 59 years, 45 were male (52.9 %), and 17 (20 %) had poor BP on the second colonoscopy. For group B, the multivariable-adjusted odds ratio (OR) for poor BP on the second colonoscopy relative to group A was 0.68 (95 % confidence interval [CI], 0.16-2.95). Adequately ingested PEG during the initial colonoscopy was associated with poor BP on the second colonoscopy (OR 4.05; 95 % CI 1.04-15.75). The two groups had similar patient discomfort rates during the second BP. Conclusions: The two groups did not differ in rescue BP failure rate. Initial BP failure after adequate consumption of 4 L PEG may be a risk factor for rescue BP failure. A stricter BP regimen should be considered for these patients. [ABSTRACT FROM AUTHOR]

Background: The impact of one-stage polypectomy (removal of all neoplasms during diagnostic colonoscopy) versus two-stage polypectomy (removal of all neoplasms during therapeutic colonoscopy following the initial diagnostic colonoscopy) on the development of metachronous neoplasms is poorly understood. Our aim was to compare the effects of one- versus two-stage polypectomy on the development of metachronous neoplasms Methods: We retrospectively reviewed the medical records of 249 patients in a tertiary center who underwent one-stage polypectomy, which was followed by one or more surveillance colonoscopy. The development of metachronous neoplasm in this group was compared with that of an age- and sex-matched two-stage polypectomy group consisting of 498 patients Results: In total, 346 (46.3 %) patients developed any metachronous neoplasm and 29 (3.9 %) patients developed advanced metachronous neoplasm. The 5 years cumulative incidences of any and advanced metachronous neoplasm were 46.2 and 5.0 %, respectively, in the one-stage group, which are not significantly different from the rates of 50.7 and 3.3 % in the two-stage group ( p = 0.94 and 0.30, respectively). The only significant risk factor for developing any metachronous neoplasm was ≥3 neoplasms at the baseline polypectomy [hazard ratio (HR) 1.75; 95 % confidence interval (CI) 1.41-2.17; p < 0.001]. The only significant risk factor for developing advanced metachronous neoplasm was advanced neoplasm at the baseline polypectomy (HR 2.37; 95 % CI 1.16-4.84; p = 0.01). One- and two-stage polypectomy did not affect the development rates of metachronous neoplasm Conclusions: The risks of developing metachronous neoplasm may be similar following one- and two-stage polypectomy. [ABSTRACT FROM AUTHOR]

Background and Aims: The role of infliximab in the treatment of patients with ulcerative colitis (UC) in Asia is still unclear. The aim of this study was to evaluate the clinical outcomes of infliximab therapy in Korean UC patients, including efficacy and predictors of response. Methods: Patients who received infliximab induction therapy for moderate to severe UC at Asan Medical Center were retrospectively analyzed. The demographic characteristics of these patients and their clinical outcomes following infliximab therapy were evaluated. Results: Of the 89 UC patients receiving infliximab induction therapy, 53 (59.6 %) were steroid-refractory and 36 (40.4 %) were steroid-dependent. At the initiation of infliximab, the median Mayo score was 9 (range 7–12). After the induction therapy of infliximab, 59 patients (66.3 %) demonstrated a clinical response at week 8, of which 29 (32.6 %) were determined to be in clinical remission. A colectomy was performed within 1 year after infliximab initiation in 11 (36.7 %) of 30 patients who displayed no clinical response to infliximab therapy, but in none of the 59 patients who showed a response to this drug ( p < 0.001). Multivariate regression analysis identified severe disease (Mayo score ≥ 11) at the initiation of infliximab ( p = 0.007) and history of cytomegalovirus colitis within 3 months prior to infliximab treatment ( p = 0.001) as independent positive predictors of nonresponse to infliximab. Conclusions: The efficacy of infliximab in Korean UC patients seems to be similar to that of previously published Western reports. Severe disease and a history of cytomegalovirus colitis are predictors of a nonresponse to infliximab. [ABSTRACT FROM AUTHOR]

Background: Early and accurate detection of adenomatous colonic polyps is a major concern in the prevention of colon cancer. Near-infrared fluorescence (NIRF) imaging with optical probes targeting specific peptides enables the noninvasive visualization and characterization of lesions. Matrix metalloproteinases (MMPs) are known to play an important role in tumorigenesis and tumor progression.Aim: To investigate the effectiveness of NIRF imaging, with a novel MMP-activatable probe based on a polymeric nanoparticle platform, in the colon cancer models.Methods: We used an azoxymethane (AOM)-induced mouse colon cancer model resembling human sporadic colon cancer and an MMP-positive xenograft tumor model. MMP expression was evaluated by Western blotting, real-time PCR, and immunohistochemical staining. NIRF imaging was performed with a novel MMP-activatable probe, an MMP-inactivatable probe, and saline. In addition, we observed the change of NIRF signal intensity after intratumoral administration of an MMP-inhibitor.Results: Multiple tumors with various sizes developed in AOM-treated mouse colons, progressing from adenomas to adenocarcinomas, with MMP expression progressively increasing in the normal-adenoma-adenocarcinoma sequence. In mice injected with the MMP-activatable probe, the NIRF signal also increased in this sequence and was highly correlated with MMP expression (p < 0.001). Tumor-background-ratios (TBR) of adenocarcinoma to adjacent normal mucosa by a novel probe were significantly higher than that of adenoma (p < 0.001). In both the AOM and xenograft models, NIRF signals of tumors decreased after treatment with an MMP-inhibitor.Conclusions: NIRF imaging using a polymeric nanoparticle-based probe may be useful for detecting early stage disease and for assessing treatment response. [ABSTRACT FROM AUTHOR]

Background: Small bowel tumors are relatively rare, and their confirmative diagnosis before surgery is not easy.Aims: This study was performed to investigate the clinical characteristics of patients with small bowel tumors who received double-balloon enteroscopy (DBE). Secondary end points were to evaluate the usefulness and safety of DBE for the diagnosis of patients with suspected SB tumors derived from other previous procedures.Methods: We retrospectively analyzed consecutive DBE examinations to explore the small intestine in eight university hospitals over a 5-year period.Results: A total of 877 DBE examinations (per oral 487, per anal 390) were performed in 645 patients (405 males, mean age 48.2 years). Small bowel tumors were diagnosed in 112 patients (17.4%), of which 38 patients had benign polyps, 29 had gastrointestinal stromal tumors/leiomyomata, 18 had lymphomas, 14 had adenocarcinomas, five had metastatic or invasive cancers, five had lipomas, and three patients had cystic tumors. The main reasons for DBE among patients with small bowel tumors were obscure gastrointestinal bleeding (OGIB, 40.2%) followed by abnormal imaging study (25.2%). The concordance rate of diagnoses based on DBE with diagnoses based on small bowel follow-through, CT, and capsule endoscopy among patients with small bowel tumors was 68.9% (42/61), 75.3% (70/93), and 78.3% (18/23), respectively. Therapeutic plans were changed due to the DBE results in 64.2% of patients with small bowel tumors.Conclusions: Approximately one-sixth of patients who received DBE had small bowel tumors, and the most common reason for DBE among patients with small bowel tumors was OGIB. DBE is a useful method for the confirmative diagnosis of small bowel tumors and has a good clinical impact on therapeutic plans and short-term clinical results. [ABSTRACT FROM AUTHOR]

Background and Aims: Researchers have not clearly described the clinical and pathogenetic features of hypoganglionosis and adult-onset Hirschsprung's disease, which cause pseudo-obstruction or intractable constipation. We conducted this study to explore these features of hypoganglionosis and adult-onset Hirschsprung's disease in Korean patients.Methods: We enrolled 24 patients pathologically confirmed as having hypoganglionosis and 11 as having adult-onset Hirschsprung's disease. We recruited 26 subjects who had undergone operation for nonobstructive colon cancer and 45 healthy volunteers as controls. We described their clinical features, investigated ganglion cells and interstitial cells of Cajal (ICC), and analyzed RET, EDNRB, EDN3, and SOX10 genes.Results: We classified hypoganglionosis patients into two groups: type I (focal type, n = 13), with focally narrowed transition zone (TZ); and type II (diffuse type, n = 11), without transition zone. Hypoganglionosis patients had significantly fewer ganglion cells than the controls, and those cells were scarcer in the transition zone than in the proximal dilated area (P < 0.05). The ICC numbers in both diseases were significantly lower than in controls; however, they were similar between transition zone and the proximal dilated area in hypoganglionosis. In adult-onset Hirschsprung's disease, two significant intronic RET polymorphic variants, IVS14-24G>A and IVS19+47T>C, were significantly associated with adult-onset Hirschsprung's disease (P = 0.0122 and 0.0295, respectively), but not with hypoganglionosis.Conclusions: Hypoganglionosis and adult-onset Hirschsprung's disease have different pathophysiologic characteristics, although their clinical presentations are similar. We suggest that there are two subgroups of hypoganglionosis: those with or without a focally narrowed transition zone with a profoundly diminished number of ganglion cells. [ABSTRACT FROM AUTHOR]

Background: Although the diagnostic and therapeutic values of double balloon endoscopy (DBE) have been investigated, the subjective tolerability to DBE has not been assessed. We aimed to evaluate patients' tolerability to DBE.Methods: We prospectively enrolled patients who underwent DBE. For the comparison of tolerability to DBE with that to esophagogastroduodenoscopy (EGD) and colonoscopy, those who had not undergone EGD nor colonoscopy were excluded. A total of 52 patients were included. All procedures were performed under conscious sedation with midazolam with or without pethidine. Patients' tolerability to DBE, EGD, and colonoscopy was assessed through an interview with a questionnaire using a 10-point Likert scale.Results: A total of 36 patients underwent both antegrade DBE and EGD under conscious sedation. The level of abdominal pain during procedures, the level of post-procedural abdominal discomfort, and the proportion of patients with persistent abdominal discomfort until the next morning were higher in antegrade DBE. However, when analyzed in 16 patients who had good quality of sedation, the differences in the level of abdominal pain during procedures and the persistent abdominal discomfort until the next morning disappeared. A total of 23 patients underwent both retrograde DBE and colonoscopy under conscious sedation. Tolerability parameters were not different between retrograde DBE and colonoscopy. Serious complications, including hemodynamic instability, did not occur during all procedures.Conclusion: Patients tolerated DBE well. DBE may be performed as comfortably as EGD and colonoscopy if the quality of sedation is good enough. [ABSTRACT FROM AUTHOR]

Background: There is no consensus regarding the degree of healing of endoscopic submucosal dissection (ESD)-induced ulcers and the optimal duration of proton pump inhibitor (PPI) treatment.Aim: To evaluate the degree of healing and the factors associated with healing of ESD-induced ulcers after PPI therapy for 4 weeks.Methods: Fifty-six patients who underwent complete ESD for adenoma or early gastric cancer were enrolled. All patients underwent follow-up endoscopy to evaluate the degree of ulcer healing after pantoprazole therapy (40 mg per day) for 4 weeks. We evaluated change in size of ESD-induced ulcers between baseline and 4 weeks, and correlated relevant factors with degree of healing of small and large ulcers.Results: At follow-up, 28 (50%) patients had large ulcers (area > 10 mm(2)). Ulcer size at 4 weeks was closely correlated with initial ulcer size (P < 0.001) and abruptly increased when initial ulcer size was larger than 4 cm. Comorbidity, procedure time, and initial specimen size were significantly associated with healing rate, but multivariate analysis showed that initial ulcer size was the only significant parameter (P < 0.015).Conclusions: Healing degree of ESD-induced ulcers at 4 weeks is dependent on initial ulcer size, indicating that duration of treatment with PPI should be dependent on initial ulcer size. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The aims of this prospective study were to document the incidence of colon immediate postpolypectomy bleeding (IPPB) according to grade, and to identify potential risk factors of IPPB in patients who have received complete colonoscopy and polypectomy because of a colorectal polyp. METHODS: This was a prospective, cross-sectional study of 5,152 patients treated at 11 tertiary medical centers between July 2003 and July 2004. Patient-related, polyp-related, and procedure-related variables were evaluated as potential risk factors for IPPB. IPPB was defined as a bleeding occurring during the procedure and was graded as G1–G4. Risk factors associated with IPPB were analyzed by univariate and multivariate logistic regression analysis. RESULTS: A total of 9,336 colonic polyps were removed in 5,152 patients, and 262 (2.8%) colorectal polyps in 215 patients presented with IPPB. Polyp-based multivariate analysis revealed that old age (≥65 yr), comorbid cardiovascular or chronic renal disease, anticoagulant use, polyp size greater than 1 cm, gross morphology of polyps such as pedunculated polyp or laterally spreading tumor, poorer bowel preparation, cutting mode of the electrosurgical current, and the inadvertent cutting of a polyp before current application were significant risk factors for IPPB. CONCLUSION: Nine factors have been found to be associated with IPPB and polypectomy should be undertaken with caution under these conditions. [ABSTRACT FROM AUTHOR]