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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]

Background: Anti-tumor necrosis factor (TNF) treatment for inflammatory bowel disease (IBD) increases the risk of tuberculosis (TB) infection. In the present study, we analyzed the clinical characteristics and risks of TB in Korean patients with IBD who received anti-TNF treatment.Methods: The study included patients with IBD who were treated using anti-TNF agents between January 2001 and June 2018 at the Asan Medical Center. Overall, 1434 patients with ulcerative colitis or Crohn's disease were enrolled. We calculated the incidence of active TB infection after anti-TNF treatment and compared the clinical characteristics of the TB group with those of the non-TB group.Results: Twenty-one patients (1.46%) developed active TB infection, and the incidence rate of active TB was 366.73 per 100,000 person-years. In total, 198 patients (14.9%) were positive for latent tuberculosis infection (LTBI), of whom only eight (4%) did not complete LTBI treatment. The age at which the anti-TNF therapy was started was significantly higher in the TB group than in the non-TB group (HR 1.041, 95% CI 1.014-1.069, p = 0.002), and as age increased, so did the incidence rate of active TB infection (linearity p < 0.001). There was no significant difference in the incidence rate of LTBI between the TB and non-TB groups (HR 0.896, 95% CI 0.262-3.066, p = 0.862).Conclusions: In patients with IBD, the incidence rate of TB increased with age at anti-TNF therapy initiation. Active treatment of LTBI may lower the incidence of TB in patients with IBD who are to undergo anti-TNF therapy. [ABSTRACT FROM AUTHOR]

Background: Many patients with ulcerative colitis (UC) in clinical remission frequently complain of bowel symptoms such as increased stool frequency (SF) and rectal bleeding (RB). However, studies on these patient-reported outcomes in patients with inactive UC are limited, especially in Korea. Therefore, we investigated the prevalence and risk factors of bowel symptoms in Korean patients with inactive UC.Methods: We investigated the prevalence of bowel symptoms in patients with endoscopically quiescent UC between June 1989 and December 2016 using a well-characterized referral center-based cohort. The Mayo clinic score (MCS) was used to evaluate bowel symptoms at the most recent visit near the date of endoscopy. Clinical characteristics of the patients were compared based on the presence or absence of bowel symptoms.Results: Overall, 741 patients with endoscopically quiescent UC were identified, of whom 222 (30%) and 48 (6.5%) had an SF and RB subscore of ≥ 1, respectively. Patients with bowel symptoms (SF + RB ≥ 1; n = 244 [32.9%]) had higher rates of left-sided colitis (E2) or extensive colitis (E3) than patients without bowel symptoms (SF + RB = 0; n = 497 [67.1%]; P = 0.002). Multivariate analysis revealed that female sex (odds ratio [OR]: 1.568; 95% confidence interval [CI]: 1.023-2.402; P = 0.039) and E2 or E3 (OR 1.411; 95% CI 1.020-1.951; P = 0.038) were the significant risk factors for increased SF.Conclusions: This study revealed that one-third of patients with endoscopically quiescent UC reported increased SF. Female sex and disease extent may be associated with bowel symptoms. [ABSTRACT FROM AUTHOR]

Background: Although endoscopic submucosal dissection (ESD) is widely used, the current status and trend in its training have yet to be fully evaluated. We aimed to investigate how ESD endoscopists have been trained in actual clinical practice. Methods: Endoscopists aged <45 years who have completed a gastroenterology fellowship or were currently in a fellowship for ≥2 years were included. We conducted a nationwide survey on the ESD training experiences of these endoscopists. Results: Among 79 young Korean endoscopists invited to participate in the survey, 68 (86.1%) trained in 24 major hospitals responded to the questionnaire. Twenty, 25, and 23 participants belonged to the second-year fellow, <5 years after training, and ≥5 years after training groups, respectively. Sixty-nine percent of the participants observed ≥50 ESD cases before starting ESD under supervision by an expert endoscopist. Additionally, 22% experienced ≥20 supervised ESDs during the training period. The proportion of the participants who underwent a hands-on course differed among the groups (≥5 years after training, 13.0%; <5 years after training, 40.0%; and second-year fellow, 50.0%; P = 0.027). ESD under supervision, observation, and hands-on course were the preferred methods for learning ESD (91.1%, 80.9%, and 35.3%, respectively). Overall, 42.6% of the participants were satisfied with their training program. More experience in supervised ESD (≥20 cases) was associated with an increased satisfaction (odds ratio, 6.65; 95% confidence interval, 1.62–36.31). Conclusions: Observation and performance of ESD under the supervision of an expert endoscopist are the primary methods for learning ESD. Hands-on course program has been used more frequently in recent years. [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]

Background and Aim: Little is known whether routine prophylaxis against Pneumocystis jirovecii pneumonia (PJP) is needed in patients with inflammatory bowel disease (IBD) on immunosuppression, especially in Asian populations. We, therefore, sought to investigate the incidence and risk factors of PJP in patients with IBD in Korea. Methods: We investigated the incidence of PJP in patients with IBD and compared the characteristics of IBD patients with PJP episodes (IBD‐PJP group) with those of matched controls (IBD‐only group) using a large, well‐characterized referral center‐based cohort. Results: Among the 6803 IBD patients (3171 with Crohn's disease and 3632 with ulcerative colitis) enrolled in the Asan IBD Registry between June 1989 and December 2016, six patients (0.09%) were diagnosed with PJP. During the 57 776.0 patient‐years of follow‐up (median 7.2 years per patient), the incidence of PJP was 10.4 cases per 100 000 person‐years, and none of these patients had received PJP prophylaxis. In case–control analysis, the IBD‐PJP group (n = 6) showed significantly higher C‐reactive protein level at diagnosis of IBD (P = 0.006), as well as higher exposure to corticosteroids (P = 0.017), than did controls (n = 24). In addition, the IBD‐PJP group showed higher rates of double (50% vs 12.5%) or triple (33.3% vs 4.2%) immunosuppression than did controls, although these are not statistically significant. Conclusions: Although the incidence of PJP in Korean patients with IBD is low, careful monitoring is necessary for the early detection of PJP. In addition to the patients receiving double or triple immunosuppression, PJP prophylaxis should be considered especially in patients with severe disease activities requiring corticosteroids. [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: 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 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 and Aim Appendectomy protects against the development of ulcerative colitis ( UC). However, the relationship between appendectomy and the clinical course of UC is complex, and could be impacted by a number of variables. The aim of this study was to compare the clinical course of UC between appendectomized patients and nonappendectomized patients in Korea. Methods Data on 2648 UC patients were retrieved from the Inflammatory Bowel Disease registry at Asan Medical Center. This retrospective cohort study compared the clinical course of UC in 68 patients who received an appendectomy before their UC diagnosis and 2544 patients who did not receive this procedure. A nested case-control study was also conducted to compare the disease course before and after appendectomy in 36 patients who received this surgery after UC diagnosis. To control for potential confounders, 144 matched controls were retrieved from among 2544 nonappendectomized patients Results In the retrospective cohort study, an appendectomy before UC diagnosis demonstrated no influence on disease extent at diagnosis, rates of medication use, proximal disease extension, or colectomy. The 10- and 20-year probabilities of receiving a colectomy were 12.7% and 20.6%, respectively, in appendectomized patients, in comparison with 8.9% and 16.4%, respectively, in nonappendectomized patients ( P = 0.81). According to the nested case-control study, an appendectomy after UC diagnosis did not change the subsequent disease course in terms of medication use, proximal disease extension, or hospital admission rate. The adjusted ratio of hospital admissions after appendectomy versus before appendectomy was 1.01 (95% confidence interval = 0.46-2.23; P = 0.97). Conclusions Appendectomies performed before or after UC diagnosis do not affect its clinical course in the Korean population. [ABSTRACT FROM AUTHOR]

Objective. Limited data are available on the incidence and risk factors of colorectal cancer (CRC) in Asian patients with inflammatory bowel disease (IBD). Material and methods. Information on 5212 Korean patients with IBD (2414 with Crohn's disease [CD] and 2798 with ulcerative colitis [UC]) was retrieved from the IBD registry of Asan Medical Center. Data on CRC incidence for the entire Korean population were derived from the Korean Statistical Information Service. Results. During 39,951 person-years of follow-up (17,679 for CD and 22,272 for UC), 30 patients (12 with CD and 18 with UC) developed CRC. The standardized incidence ratio (SIR) of CRC was 6.0 (95% confidence interval [CI], 3.10-10.48) for CD and 1.68 (95% CI, 1.00-2.66) for UC; it was 9.69 (95% CI, 5.01-16.93) for CD with colonic involvement and 4.31 (95% CI, 2.46-7.00) for extensive UC. The SIR was also increased in patients diagnosed with IBD at younger than 30 years old. CRC location was the low rectum in 11 of 12 CD patients (91.7%). The cumulative probability of rectal cancer was higher in CD patients with a perianal fistula than in those without a perianal fistula ( p = 0.02). Conclusions. A high prevalence of perianal fistulas in Korean CD patients may be the cause of the predominance of low rectal cancer in this population and the higher SIR of CRC in Koreans than in Westerners. In contrast, the SIR of CRC in Korean UC patients may be similar to that in Western UC patients. [ABSTRACT FROM AUTHOR]